How to fix
Error Code 1500 “Another Installation is in progress”
on Windows

None of the downloads can be completed due to the Error Code 1500 with a message "Another Installation is in progress. You must complete the installation before continuing this one." I’ve checked the list of active downloads, but I can’t see any downloads in progress. Can someone explain to me what is going on?

"Another Installation is in progress. You must complete the installation before continuing this one" error with a Code 1500 is not a novelty among Microsoft[ref en-3] users. Many have already experienced this bug on Windows Vista, XP, 7, and 8, but, at the moment of writing, the vast majority of the error code 1500 reports are coming from people who own Windows 10 PC[ref en-2] and laptops.

The error occurs when the PC’s owner attempts to download programs to the system. The download or installation process gets stuck and the "Another Installation is in progress” error shows up. As the message reports, a particular application cannot be installed due to several MSI installers running on the system at the same time. Therefore, you should check the list of downloads in execution and terminate them or wait until the download will be finished.

However, most people claim that the error 1500 emerges even if no downloads are currently carried out. In this case, the culprit may be the active In-progress keys left from an earlier software installation. Thus, to fix the "Another Installation is in progress” error on Windows, you may perform several fixes manually.

Fixing Error Code 1500 "Another Installation is in progress” on Windows

Option 1. Disable background software processes

1. Open Task Manager and expand the Processes tab.

   

2. Find msiexec.exe process, click on it, and select End Task.
3. Do the same with the installer.exe and setup.exe processes.
4. To check if these processes are completely disabled, open Details tab.
5. If these processes are in the Details list, disable them there as well.

Option 2. Delete the Installation References

1. Press Windows key + R, type regedit, and press Enter to open Registry Editor.
2. Navigate to the HKEY_Local_Machine\\Software\\Microsoft\\Windows\\Installer\\InProgress sub-key.

   

3. Select the InProgress subkey and double-click on the Default string.
4. Remove its value and click OK to save the changes.

Option 3. Restart Windows Installer service

1. Press Windows key + R, type services.msc, and press Enter.

   

2. Find Windows Installer service and double-click on it.
3. Click on the Startup type of this service and select Disable or Stop button.
4. Click Apply and OK to save the changes.
5. Finally, reboot the system.
6. When the system boots up, re-open Services and find Windows Installer service as explained above.
7. Click on its Startup type and select Start.
8. Click Apply and OK to save the changes and close everything.

If none of these steps helped, you can run SFC and DISM scans to check the system for corrupted system files.[ref en-1] Alternatively, you can use a professional optimization utility like [d1].