PROBLEM


When installing Altaro VM Backup, the error  Another installation is in progress. You must complete that installation before continuing this one  is encountered.




CAUSE


The Windows Installer process can only run one installation at a time. Complete the other installation or wait a few minutes for the background installation taking place completes.



SOLUTION


This Error indicates that the Windows Installer Service is currently being used for another installation. Aside from other program's Installations, Windows Updates can also use the Windows Installer service and will therefore need to complete before running another installation. 


If there are currently no other installations in progress, then it is likely that a previous installation was unsuccessful and did not close properly, in this case you can end the Windows Installer Process manually as follows:

  1. Open Task Manager and navigate to the "Details" tab
  2. Locate and end any "MSIExec.exe" tasks you see
  3. Run the Altaro installer again