Update: I have been able to open a termbase by double-clicking on the file in Windows Explorer. After doing that, the only Termbase that was listed in the Select Termbase dialog was the one I just opened, and Multiterm didn't crash on opening the dialog. However, it would be nice to know where the list of termbases is stored.

Francesco Monticelli 

Probably in this file:

c:\Users\[USERNAME]\AppData\Roaming\Trados\MultiTerm\MultiTerm17\UserSettings.xml

Thank you Paul . I had a look and it seems like this might actually be were the settings are stored. However, Looking at the file, I wouldn't recommend making any changes directly to that file. So it's good that I managed to find a workaround that didn't require doing that.

Thank you Paul . I had a look and it seems like this might actually be were the settings are stored. However, Looking at the file, I wouldn't recommend making any changes directly to that file. So it's good that I managed to find a workaround that didn't require doing that.

Francesco Monticelli 

Indeed it is... I thought that was what you were asking.  

Given the problem you were having one solution could be to remove the sections related to the offending termbase altogether and then just open it in MultiTerm from wherever it's located to add it back again.

But good you found a workaround!