"Edit - Calculate MD5 Checksums" not working

I downloaded and I am evaluating Directory Opus. So far, I like it.

But, when I highlight a file(s), and the select “Edit - Calculate MD5 Checksums”, it doesn’t work. Nothing is displayed. Is this a bug, or has this feature been disabled in the trial?

Note: When I add the MD5 SUM column in the display, I can see the checksums. But this takes longer. I prefer to be able to just get a quick checksum on a file/dir that I highlight, and to not have the checksums displayed for all files/dirs in a separate column.

By default files above a certain size are skipped; you can adjust the limit (or disable it completely) using the Preferences / Miscellaneous / Advanced [Limits]: max_md5_file_size option.

Note that Edit - Calculate MD5 Checksums ignores the size limit, so you can use that to explicitly calculate checksums for larger files without needing to increase the limit.

If it isn't working, one possibility is that something has the file open for writing, and hasn't closed it yet.

Another possibility is that an antivirus or privacy guard tool is blocking Opus from accessing the file. Some tools, including Windows Defender, can be particularly bad in this regard, by breaking things and failing to inform you that they're doing it. ( Problems caused by Windows Defender (strange behavior when using Opus) )

I did a test to make sure it's still working here: