I was translating a project like usual and decided to mess around with settings for no good reason. This time I deleted everything from "Do not match" because I wanted to see how it affects matching. The result was somewhat surprising as I got a TM error (can't remember which exact error) and had to restart CT because my shortcut for adding to memory and moving on to next segment wasn't working.
After restarting, I noticed that my main translation memory was pretty much empty: 120,000+ segments gone just like that. The only segment left is the very first segment in that TM - translated years ago. My project TM wasn't affected at all which is weird because it was the only one that wasn't a "Read-only memory".
Any guesses what might have caused this? I've checked that the segments are truly gone from the file and not just invisible or anything like that.
Luckily I have a backup memory so I didn't really lose anything. Pretty scary nonetheless.
It would be good to know the actual error message. You may also have changed other TM settings that turned off the read only mode.
I wish I had paid more attention to the message. I might be able to recognize it if I saw it again but I cannot even begin to guess what it was without any reference. That's also true about the mode, I may have turned it off, but I suppose there's no way to know for sure. A mystery indeed.
Am I right to assume that there is no "legitimate" setting that would wipe all but one segment from the memory?
Perhaps some filter or different language code was selected for this TM?
What do you mean by that? I don't think a language code or filter would explain how the tmx file itself got cleared (from 80MB to 2KB) – maybe I misunderstood the question.
For example, if you choose a filter option in TM start-up panel (e.g Filter langauges), CT will extract the filtered segments. Then, saving the filtered TM under the same name as the original TM will overwrite it. However, it is only a guess in this specific case.
Now I understand, thanks for explaining. In this case, I was already working on the project – yes yes, I shouldn't change any important settings in the middle of a project – and didn't close or open any translation memories or change their settings. On purpose at least.
Do backups before you mess with your important data.
That is indeed why I had a backup file. Still, I wouldn't consider changing match settings as messing with my data, I guess I was just unlucky that one time.