When you try to install Microsoft Office or to start an Office program, you receive the following error message:
Error 1500. Another installation is in progress. You must complete that installation before continuing this one.When you click Retry, the message is displayed again. When you click Cancel, the installation stops.
Two or more instances of the Msiexec.exe service cannot be launched at the same time for two different products. One install or repair process must finish before the other process can be launched.
To resolve this issue, restart the computer.
For more information about similar messages, click the following article number to view the article in the Microsoft Knowledge Base:
822454 "ERROR_INSTALL_ALREADY_RUNNING" error message when you run the Setup program to install Office programs