How to fix Windows update error 0x800700a1?

Error 0x800700a1 means Windows Update or the update installer was sent to a folder that does not exist: Win32 error 161, "The specified path is invalid." Most often the temporary folder or the update cache is missing, moved or broken. Check where TEMP points first, then empty C:\Windows\Temp.

Facts checked on 15 October 2026. Steps written for Windows 11 (25H2 and 26H2) and Windows 10 22H2.

What Windows update error 0x800700a1 means

0x800700a1 is an ordinary Windows system error in the eight-digit form that Windows Update prints. The first half, 0x8007, marks a Win32 error wrapped for the update components. The second half, 00A1, is 161 in decimal, and Microsoft's list of system error codes gives 161 the text "The specified path is invalid." The constant is ERROR_BAD_PATHNAME.

So the message is about a folder, not about the update itself. Somewhere in the chain, a path points to a folder that does not exist, to a drive letter that is gone, or is written in a form Windows cannot read. The fixes below check those folders one by one, starting with the ones an update uses first.

Why error 0x800700a1 happens, from most to least likely

Microsoft has not published a cause for this code in Windows Update. The ranking below follows what the code says, a bad path, and the one solved case we read, where emptying C:\Windows\Temp let the update install. Each cause points to the fix that matches it.

How to fix Windows update error 0x800700a1

Fixes 1 and 2 take five minutes and change nothing important, so everybody starts there. Fixes 3 and 4 repair the update cache and the update service. Fixes 5 and 6 are the general repairs. Fix 7 rebuilds Windows and keeps your files and apps.

Fix 1. Check that the TEMP and TMP folders exist

5 minutesLow riskAlways first, and above all after you removed a drive, moved user folders or used a cleaner or tuning tool.

Installers unpack update files into the folder that TEMP and TMP name. If that folder or its drive is gone, every attempt ends with "The specified path is invalid", whether you use Windows Update or a .msu file.

1. Press Win + R, type cmd and press Enter.
2. Show where the two variables point.

   echo %TEMP%
   echo %TMP%

3. Copy each path into the address bar of File Explorer and press Enter. If the folder opens, this cause is ruled out.
4. If a path does not open, press Win + R, type sysdm.cpl and press Enter. Open the Advanced tab and select Environment Variables.
5. Under User variables, set TEMP and TMP to %USERPROFILE%\AppData\Local\Temp.
6. Under System variables, set TEMP and TMP to %SystemRoot%\TEMP.
7. Select OK in every window, restart the PC and try the update again.

Fix 2. Empty or recreate C:\Windows\Temp

5 minutesLow riskThe TEMP check was clean, the folder is missing, or it holds a large pile of old files.

Windows Update runs under the system account, which uses C:\Windows\Temp, not your own TEMP folder. In the solved KB3205401 case on Server Fault, emptying this folder was the only step that let the update install.

1. Close open programs and restart the PC once, so fewer files are in use.
2. Press Win + R, type %windir%\Temp and press Enter. Select Continue if Windows asks for permission.
3. If Windows says the location is not available, the folder is missing. Open Terminal (Admin) or Command Prompt as administrator and create it.

   md %windir%\Temp

4. If the folder opens, press Ctrl + A to select everything, then press Delete.
5. When Windows says a file is in use, tick Do this for all current items and select Skip.
6. Restart the PC and try the update again from Settings > Windows Update.

Only delete the contents, never the Temp folder itself. A few files stay because they are in use, which is normal. If you want the general clean-up of temporary files as well: Free up disk space and delete temporary files

Fix 3. Check the update cache folder and reset Windows Update

15 minutesLow riskFixes 1 and 2 did not help, you moved SoftwareDistribution to another drive, or the PC had other update errors before this one.

Windows Update keeps its downloads and its database in C:\Windows\SoftwareDistribution. If that folder was replaced by a link to a drive that is gone, every path inside it is invalid. A reset gives Windows a new, empty cache at the default place.

1. Right-click Start and select Terminal (Admin). On Windows 10, search for cmd and select Run as administrator.
2. List the links inside the Windows folder.

   dir /aL %windir%

3. If SoftwareDistribution appears in the list with JUNCTION or SYMLINKD, note the target in brackets. If that drive or folder is gone, the link is the cause.
4. Reset the update components with the steps below. They stop the services, rename the cache folders and start the services again, so Windows creates a normal folder.

1. Open Command Prompt as administrator. Type cmd in the search box, right-click Command Prompt and select Run as administrator. Select Yes when Windows asks for permission.
2. Stop the update services. Type the commands below and press Enter after each one. If Windows says that other services depend on Cryptographic Services, it stops them too. A message that a service is not started is fine.

   net stop wuauserv
   net stop bits
   net stop cryptsvc

3. Delete the download queue files. This clears the list of downloads that the Background Intelligent Transfer Service keeps. If Windows says it cannot find the files, continue.

   del "%ALLUSERSPROFILE%\Application Data\Microsoft\Network\Downloader\qmgr*.dat"

4. Rename the update cache folders. Renaming keeps a copy in case you need it; Windows creates new, empty folders when the services start again. If you get Access is denied, a service is still running: repeat the previous step.

   ren %systemroot%\SoftwareDistribution SoftwareDistribution.old
   ren %systemroot%\System32\catroot2 catroot2.old

5. Start the services again. Type the commands below and press Enter after each one. The requested service has already been started is fine: Windows started it on its own.

   net start cryptsvc
   net start bits
   net start wuauserv

6. Restart and check for updates. Restart the PC. Then select Start > Settings > Windows Update > Check for updates. The first check can take longer than usual because everything is downloaded again.

These steps were written for Windows 11 and Windows 10 (the steps are the same). The full page with the other versions and what each result means: Reset Windows Update components

Then run the built-in troubleshooter once, which checks the same components: Run the Windows Update troubleshooter

Fix 4. Check that the Windows Update and BITS services can start

10 minutesLow riskEvent Viewer shows "The Windows Update service terminated with the following error: The specified path is invalid", or the update never starts.

This Event Viewer message means the service itself stopped on a bad path, before any download. Checking its settings shows whether the service points to the right program and runs as it should.

1. Right-click Start and select Event Viewer. Open Windows Logs > System.
2. In the right pane select Filter Current Log, type 7023 in the event ID box and select OK. Read the newest entries for Windows Update or Background Intelligent Transfer Service.
3. Open Terminal (Admin) or Command Prompt as administrator.
4. Show the settings of both services.

   sc qc wuauserv
   sc qc bits

5. Check that BINARY_PATH_NAME starts with C:\Windows\system32\svchost.exe -k netsvcs for both, and that START_TYPE is not DISABLED.
6. If a service is disabled, set it back to Manual in Services and start it, as shown below. If the path is different, do not edit the registry by hand: go to Fix 5 and then Fix 7.

1. Open Services. Press Windows+R, type the command below and press Enter. You can also type Services in the search box on the taskbar and open the app.

   services.msc

2. Find the service. The list is sorted by Name. Click any row and type the first letter of the service to jump to it. Check the Status column (Running or empty) and the Startup Type column.
3. Restart the service. Right-click the service and select Restart. If the service is not running, select Start instead. Wait until the progress window closes.
4. Open its properties to change the startup type. Only if your guide says so: double-click the service. The General tab shows the Service name (used in commands), the Startup type and the Service status.
5. Set the startup type and apply. Choose the type from the Startup type list (Automatic, Automatic (Delayed Start), Manual or Disabled), select Apply, then Start if the service should run now, and OK.

These steps were written for Windows 11 and Windows 10 (the steps are the same). The full page with the other versions and what each result means: Check and restart Windows services

Fix 5. Repair system files with SFC and DISM

30 minutesLow riskThe folders and services look fine, or Fix 4 found a service setting you should not edit by hand.

Damaged system files can break the update components that build the paths. SFC and DISM put back the original files from Windows' own store. This is a general repair, so it comes after the checks that are specific to error 161.

1. Open an elevated command window. Right-click Start and select Terminal (Admin), or type cmd in the search box, right-click Command Prompt and select Run as administrator. Select Yes when Windows asks for permission.
2. Run DISM first. Type the command below and press Enter. DISM downloads clean copies of damaged components from Windows Update, so it can take several minutes. Wait until it says The operation completed successfully.

   DISM.exe /Online /Cleanup-Image /RestoreHealth

3. Run System File Checker. In the same window, type the command below and press Enter. Do not close the window until the verification reaches 100%.

   sfc /scannow

4. Read the result and restart. Compare the last message with the table below this guide, then restart the PC so that repaired files are loaded.

These steps were written for Windows 11 24H2 and 25H2. The full page with the other versions and what each result means: Run DISM and SFC to repair Windows system files

Fix 6. Install the update by hand from the Microsoft Update Catalog

20 to 40 minutesLow riskOne KB keeps failing, or the PC gets updates from a company WSUS server.

A manual install skips the Windows Update download chain. In the solved Server Fault case the update failed from WSUS and installed after it came from Microsoft Update directly, once C:\Windows\Temp was empty.

1. Check your Windows version. Press Windows key + R, type winver and press Enter. Note the version (for example 25H2) and the OS build.
2. Find the KB number. Open Settings > Windows Update. A failed or pending update is listed with its KB number; earlier ones are under Update history.
3. Check the processor type. Open Settings > System > About and look at System type: an x64-based PC needs the x64 file, an ARM-based PC (for example Snapdragon) needs the arm64 file.
4. Search the catalog. Open the Microsoft Update Catalog at catalog.update.microsoft.com in your browser, type the KB number (for example KB5124010) in the search box and press Enter.
5. Pick the right row. Find the row whose title names your Windows version and your processor type (x64-based or arm64-based) and select Download on that row.
6. Download every file listed. A window lists one or more .msu links. Download all of them into one empty folder, for example C:\packages. On Windows 11 24H2 and later the list can include earlier checkpoint updates that the new one needs.
7. Install a single file. If there is only one file, double-click it and confirm the installation in the Windows Update Standalone Installer.
8. Install several files with DISM. If there are several files, open an elevated Terminal or Command Prompt and run DISM with the newest file. DISM finds the other files in the same folder and installs them in the right order.

   DISM /Online /Add-Package /PackagePath:C:\packages\<newest-file>.msu

9. Restart. Restart the PC when the installation finishes, then run winver again: the OS build should have changed.

These steps were written for Windows 11 24H2 and later; Windows 10 22H2. The full page with the other versions and what each result means: Install an update from the Microsoft Update Catalog

• Save the file to a short local path, such as C:\packages. A network share or a drive that may disconnect gives the installer another path to lose.
• The same error by hand. The download was never the problem. Go back to Fixes 1 and 2, then go to Fix 7.

Fix 7. Reinstall Windows over itself and keep your files and apps

1 to 2 hoursLow riskEvery other fix failed, or Fix 4 showed a service path that is wrong.

A repair install writes a fresh copy of Windows, with default folders, services and variables, and keeps apps, files and settings. It resets every path that error 161 could be about at once.

1. Open Recovery in Settings. Open Settings > System > Recovery. Next to Fix problems using Windows Update, select Reinstall now. This keeps your apps, files and settings.
2. Start the reinstall. Choose whether the PC may restart on its own 15 minutes after the installation, then select OK.
3. Wait and restart. Windows Update downloads and installs a repair copy of your current Windows version. Keep the PC plugged in and online, and restart it when asked.

These steps were written for Windows 11 22H2 and later. The full page with the other versions and what each result means: Reinstall Windows without losing files

On Windows 10 22H2, or when Reinstall now is missing, use installation media. On Windows 10 the Media Creation Tool offers Upgrade this PC now. On Windows 11, download the ISO from Microsoft's software download page, right-click it, select Mount and run setup.exe. Check that Keep personal files and apps is chosen before you select Install.

Windows 10 left support on 14 October 2025. If the PC can run Windows 11, the same repair install is the moment to move to it.

If 0x800700a1 is still there: logs, work PCs and SCCM

When the error survives every fix, the next step is a person who reads update logs. Microsoft Q&A and the Sysnative Windows Update forum both take such cases. Collect the logs right after a failed attempt, so the times match.

PowerShell (administrator): write the Windows Update log to the desktop

Get-WindowsUpdateLog

• What to send: WindowsUpdate.log from the desktop, the newest 7023 events from Event Viewer, the output of echo %TEMP% and winver, the KB number and what you already tried.
• One test with the antivirus paused. If you use an antivirus other than Microsoft Defender, pause it for one attempt and turn it back on right after: Turn off Microsoft Defender protection for a moment
• A work or school PC. Updates may come from your organization's WSUS or Configuration Manager server, and its settings decide the paths. Send the logs to your IT team before a repair install.
• Is it hardware? A path error is not a hardware fault by itself. If drives disappear and come back, or chkdsk reports errors, check the drive: Check a disk for errors (chkdsk)

How to keep error 0x800700a1 from coming back

Each point follows from what the code means. Error 161 appears when a path that Windows was given cannot be used. Anything that moves, removes or redirects the folders an update needs brings the same error back with the next update.

Frequently asked questions

What does error 0x800700a1 mean?

It means Windows was given a folder path it cannot use. The code is Win32 error 161 in the form Windows Update prints, and Microsoft's text for 161 reads "The specified path is invalid". The folder may be missing, may sit on a drive that is no longer connected, or may be written wrongly. With updates, the usual suspects are the TEMP folder, C:\Windows\Temp and the update cache, which is why Fixes 1 to 3 check them first.

What does "The Windows Update service terminated with the following error: The specified path is invalid" mean?

It is the Event Viewer form of the same error. Service Control Manager writes it to the System log when the Windows Update service stops on a path it cannot use. It points at the service or its working folders rather than at one update. Check the TEMP folders and C:\Windows\Temp first, because the service needs them, then check the service settings with sc qc wuauserv as in Fix 4. If the service path is wrong, a repair install is safer than a registry edit.

Why does the manual install fail with 0x800700a1 too?

Because the bad path is on the PC, not in the download. The Windows Update Standalone Installer unpacks the .msu file into a temporary folder, just like Windows Update does. If that folder is missing, the manual install shows "Installer encountered an error: 0x800700a1" with "The specified path is invalid". Fix the TEMP variables and C:\Windows\Temp first, save the .msu file to a short local path such as C:\packages, and run it again.

What is SCCM error 0x800700a1?

It is the same Win32 error 161 inside a Configuration Manager or MDT task sequence. It means a path that the sequence uses, such as a package location or the target drive, could not be used. The one report we read failed at the Install Operating System step on one hardware model only, and it had no published answer, so we could not confirm a cause. Read smsts.log for the path just before the error and check the drive letter of the target disk.

Is 800700a1 the same as 0x800700a1?

Yes. Some tools and logs drop the 0x prefix, and some write the letters in upper case, as 800700A1. All of them are the same error: Win32 error 161, "The specified path is invalid." Searches for the short form land on the same causes and the same fixes. Every fix on this page applies, starting with the TEMP check in Fix 1.

Is 0x800700aa or 0x800700ea the same error?

No. The last two digits change the meaning. 0x800700aa is Win32 error 170, "The requested resource is in use", which often shows up as "Failed to start repair solution" in the Windows Update troubleshooter. We have a separate guide to error 0x800700aa. 0x800700ea is Win32 error 234, "More data is available", a different problem again. Check the exact code on your screen before you follow any guide.

Can the Microsoft Store show 0x800700a1?

Users report the code in the Microsoft Store as well, for example when an app download stops. The meaning is the same: a folder the download needs cannot be used. Fixes 1 and 2 apply as they are. If they do not help, reset the Store app, which empties its own cache: Reset the Microsoft Store. We did not read a solved Store case, so we cannot say which cause is most common there.

Will a repair install delete my files or programs?

Not when you keep personal files and apps. Reinstall now in Settings > System > Recovery on Windows 11, Upgrade this PC now in the Windows 10 Media Creation Tool and setup.exe from mounted media are all built to keep your files, apps and settings. With setup.exe, check that Keep personal files and apps is chosen before you select Install. Back up your important files anyway, because a repair install is a large operation, and some apps may ask you to sign in again.

I searched in French or on a work computer. Does this page apply?

Yes, if your screen shows 0x800700a1. Windows prints the same code in every language, and the commands on this page are typed the same way everywhere, only the menu names are translated. On a work computer (ordinateur d'entreprise), updates may be managed by your IT team through WSUS or Configuration Manager. Try Fixes 1 and 2, which change nothing the IT team controls, and send them the logs before you try a repair install.