Office 365 suite installs are updated regularly these days and sometimes things go wrong. Sometimes when it goes wrong, it is stuck with a cryptic bad image error involving the ApiClient.dll file. You can’t launch any Office apps. You can’t repair the install. You can’t even uninstall it without getting this error and it crashing. Sit back, relax. Here is how you fix it.

Potential Quick Fix, Restoring the ApiClient.dll from backup:

This one is becoming less and less common for a fix since the last several Office updates have done any with the auto backup of this file. However, you may still be able to. In the past the folder %InstallDrive%\Program Files\Microsoft Office 15\ClientX64 would have some of the DLL files saved as a .bak file.

Simply deleting the ApiClient.dll, renaming this file bak file to match it, and rebooting would work. Recently however, I have not been seeing this option available to exploit.

If you have a regular backup of you entire system you might want to try restoring the ApiClient.dll file. I have done this with mixed results. Sometimes it works, sometimes it doesn’t. I suspect the problem involves more than the ApiClient.dll when it doesn’t and requires a re-install.

Uninstalling the borked Office install:

If the above isn’t an option you are in a place where we need to get Office ripped out but can’t via normal methods. Microsoft has some tools to help. Go here to get Office uninstalled. Choose option 2. If the uninstall tool does not work, try option 3 to uninstall it manually. You will then be able to re-install Office 365 which should work at this point.

Restore from Backup or System Restore:

If you are still stuck for whatever reason it may be time to go back in time with either an image backup or system restore point. Keep in mind this can affect other programs that have been installed or updated since your backup or restore point was created. In addition, Windows updates will have to be installed again if they were installed since the last backup or restore point. This can be more trouble than it is worth which is why restoring from backup or restore point is always a last resort. Backups and restore points are always nice to have as a fallback so make sure it is an option if you don’t have this in place. It is free so do it now!

Happy Office 365 ordeals!