Error 1618
Another installation is already in progress. Complete that installation before proceeding with this install.
Windows Installer only runs one installation at a time. Something else is using it, often invisibly, and the fix is to find or end that process rather than to retry.
What it actually means
MSI takes a global lock. Any other install, uninstall, repair or automatic update holds it, and background updaters frequently do so without showing a window, which is why the message seems wrong.
How to fix it, in order
Ordered by how often each one is the answer, not by how clever it sounds.
- 01Wait two minutes and retry. Background updaters usually finish on their own.
- 02Close obvious candidates: Microsoft Store, any updater running in the system tray, and Windows Update if it is mid-install.
- 03Open Task Manager and look for msiexec.exe. If one is running with no visible window and has been there a while, end it.
- 04If it persists, restart. That releases the lock reliably and is faster than hunting for the holder.
- 05In an elevated terminal, "net stop msiserver" then "net start msiserver" restarts the Windows Installer service without a reboot.
Common questions
- How do I fix error 1618?
- Something else is using Windows Installer. Wait a couple of minutes, close any updater or the Microsoft Store, end a stray msiexec.exe in Task Manager, or restart. Restarting is the most reliable fix.
Before you retry the installer
If the package came from anywhere other than the publisher, confirm it is the file they actually shipped. Check its SHA-256 against our index, which settles in seconds whether you are debugging an installer or a damaged download.