If you want to switch all databases to multi user mode, you can use my cursor script below:
This Script change all databases of instance which are in a state MULTI_USER mode, except system databases (Master, Model, MSDB and TempDB). However, there can be problem with open connection on database, in this case ALTER database failed! Therefore use my script for kill all open connection on database - HERE!
The result should look like this:
See you next time!