Like all other versions of the Windows Operating System, Windows 10 cannot install a program using Windows Installer while the installation for another program is already running. If a user does try to install a program via Windows Installer while another installation is already running, Windows displays an error message that reads:
“Error 1500. Another installation is in progress. You must complete that installation before continuing this one.”
If you see this error message while trying to install an application, simply wait for the already running installation to finish or close the already running installation and proceed with the new one. Unfortunately, there have been reports of this error message sometimes showing up when Windows 10 users try to install a program even though there is no other installation running in the background and/or any previously running installations have already finished.
If you are trying to install an application on a Windows 10 computer and are being met with Error 1500 even though there are no other installations running in the background, the following are some of the most effective solutions that you can use to try and resolve the problem:
Solution 1: Run an SFC scan
Running an SFC scan is the most basic countermeasure to a problem such as Error 1500 as it is capable of analyzing all system files for corruption and other issues and repairing/replacing any system files that may be causing problems. To run an SFC scan on a Windows 10 computer, simply follow this guide.
Solution 2: Close background processes that may be causing the problem
The Error 1500 error message can be triggered by lingering background processes from installations that were previously running on the affected computer. If residual background processes from previous program installations are causing this problem, you can fix it by simply closing the offending background processes in the Task Manager. To do so, you need to:
- Press Ctrl + Shift + Esc to launch the Task Manager.
- In the Task Manager, navigate to the Processes
- One by one, locate and click on as many of the following processes as you can find in the list of running Background processes to select them, and click on End task:
- Once the processes have been forcefully terminated, close the Task Manager.
- Try running the installation that was affected by this problem once again, and the application should be successfully installed on the computer this time.
Solution 3: Delete any active installation status references from the Registry
When an installation is in progress, an active installation status reference is added to the computer’s Registry, and this reference is removed once the installation finishes. However, an installation may sometimes fail to remove the active installation status reference from the Registry, and this can lead to the user seeing Error 1500 the next time they try to install a program on their computer. To manually delete any active installation status references from the Registry, you need to:
- Press the Windows Logo key + R to open a Run
- Type regedit into the Run dialog and press Enter to launch the Registry Editor.
- In the left pane of the Registry Editor, navigate to the following directory:
HKEY_LOCAL_MACHINE > Software > Microsoft > Windows > Installer
- Click on the InProgress sub-key under the Installer registry key in the left pane of the Registry Editor to have its contents displayed in the right pane.
- In the right pane of the Registry Editor, double-click on the (Default) registry string value to modify
- Erase whatever is in the string value’s Value data field, and click on OK.
- Close the Registry Editor.
Once done, try running the installation you were experiencing the problem with before and see check to see whether or not the problem has been fixed.
Solution 4: Stop and then restart the Windows Installer service
Since you are experiencing this issue because Windows Installer thinks that it is trying to install two programs on your computer at the same time instead of just one, stopping and then restarting the Windows Installer service is a pretty solid bet for getting rid of this issue if none of the solutions listed and described above worked for you. In order to apply this solution to your computer, you need to:
- Press the Windows Logo key + R to open a Run
- Type services.msc into the Run dialog and press Enter to launch the Services Manager.
- Scroll down through the list of services, locate the Windows Installer service and double-click on it.
- Click on Stop to stop the service. Alternatively, you can also open the dropdown menu in front of Startup type: and click on and select Disabled – it will have the same effect in the long run.
- Click on Apply and then on OK.
- Restart your computer.
- When the computer boots up, repeat steps 1-3.
- If you clicked on Stop in step 4, click on Start. If you set the Windows Installer service’s Startup type to Disabled in step 4, open the dropdown menu in front of Startup type: and click on and select Manual.
- Click on Apply and then on OK, and close the Services Manager.
Run the installation that was displaying Error 1500 to you before and see whether or not the installation completes successfully this time.