MultiTerm 2014 crashes on "unknown exception"

When I add new terms in MT2014 while I am working on Trados Studio 2014, it crashes and reports "unknown exception". I need to force Studio to close and reopen to continue my work. This issue happens a few times already. How can I fix this problem? By the way, this issue happens in windows 8.1 and windows 10, in words 2013 and words 2016.