Monica Lemons 

Monica Lemons said:

How can I recover it?

If it's not in your recycle bin, and if you don't have a backup somewhere then you are probably out of luck. The MTF and MDF files won't contain enough information to put your termbase back together.

Thank you, Paul!

Can such huge files disappear for no good reason?

I didn't update, or modify any Trados files.

Monica Lemons 

I think they could disappear for many reasons:

Did you store them in OneDrive or some other network folder?  It's possible it became cloud only and because it's huge MultiTerm can't see it anymore to use it.  Although if this is the case you'd at least see it under File -> Explorer even if it's only a footprint and not the actual file.

You may have accidentally deleted the files, or they could have been removed by someone else who uses your computer.  This can happen especially if the files were located in commonly accessed folders.

Malicious software can sometimes delete or hide files.  If your computer was infected by a virus or malware, it might have affected your files, particularly if they were large and noticeable targets.

Hard drives can develop bad sectors or other forms of corruption over time.  Large files, due to their size, are more likely to be affected by such errors, leading to their disappearance or inaccessibility.  If there are issues with the file system (like corruption in the Master File Table for NTFS drives), files might disappear.  Such problems can occur due to improper shutdowns, hardware failures, or software glitches.

Some system maintenance software or cleanup tools can mistakenly identify large files as unnecessary or temporary and delete them during clean-up processes.

Monica Lemons 

I think they could disappear for many reasons:

Did you store them in OneDrive or some other network folder?  It's possible it became cloud only and because it's huge MultiTerm can't see it anymore to use it.  Although if this is the case you'd at least see it under File -> Explorer even if it's only a footprint and not the actual file.

You may have accidentally deleted the files, or they could have been removed by someone else who uses your computer.  This can happen especially if the files were located in commonly accessed folders.

Malicious software can sometimes delete or hide files.  If your computer was infected by a virus or malware, it might have affected your files, particularly if they were large and noticeable targets.

Hard drives can develop bad sectors or other forms of corruption over time.  Large files, due to their size, are more likely to be affected by such errors, leading to their disappearance or inaccessibility.  If there are issues with the file system (like corruption in the Master File Table for NTFS drives), files might disappear.  Such problems can occur due to improper shutdowns, hardware failures, or software glitches.

Some system maintenance software or cleanup tools can mistakenly identify large files as unnecessary or temporary and delete them during clean-up processes.

I found it in Multiterm

Total No of entries 17017; it was partially moved from "SDL" to "Documents/Translations" folder.

Smaller Termbase, but praise God, I didn't lose it!

Thanks so much for your help!

Monica Lemons 

Glad you found it... now take a back up and store it somewhere safe!!

That's exactly what I'm doing!

I'll make copies of all my TMs, Termbases, AutoSugests...

Thanks a million!