Roll back an Outlook version to a previous version.

Sometimes Outlook as part of O365 may block some functionality of custom software you use.

An example is when Outlook ran an update on 20 January, it stopped working with a client’s custom software they were using, namely if they wanted to email a supplier a remittance from within their custom database software, it would open the email program (Outlook), and insert a string of characters in the To: Field and, same for the subject line.

The immediate work around was for the users to edit the To: and Subject lines.

Then, upon investigation, it appeared the latest update (Build 12430.20184) had broken functionality. It needed to be rolled back to 12325.20344

To do this, first disable updates within Outlook. File > Office Account > Update Options > Disable updates.

Run the commends below into command prompt (run as administrator):

cd %programfiles%\Common Files\Microsoft Shared\ClickToRun\

Press Enter

OfficeC2RClient.exe /update user updatetoversion=16.0.12325.20344

Press enter.

If run correctly, you will see a downloading office updates window appear.

It takes about 20 minutes for the older update to download, then roll back the Outlook version.