Directory Opus crashes all the time

I am on Directory Opus Pro 12.17 Build 7198 x64, with OS Windows 10.0 (B:18362 P:2 T:1) SP 0.0.
Lately when I go to a directory and click on a filename, Directory Opus immediately crashes and restarts.
What can I do about this?

Click with which mouse button?

After a restart of the PC I cannot reproduce the problem: it seems to work again now.
But still: what could cause this?

It depends which button you were clicking, as Jon's question suggested.

It's usually due to a shell extension something has installed.

Thanks! I will take this into account.