Now I used SQL Lite Expert Pro and it seems it could repair the TM :-)

Isabelle Queinnec 

That's great... presumably this one?

https://www.sqliteexpert.com/

What features in this did you use to repair the database?  I'm interested since this isn't free compared to DB Browser for SQLite which is.  Did you have to use a SQL script or was there some some of feature for this very purpose?

Paul 
Yes, I downloaded it here:
www.sqliteexpert.com/download.html
I took the SQLite Expert Professional 5.x (trial version)

After installing, I did
"Open" in the menu above
"All files" so it can see the sdl database
took my corrupted database
It opened it
"Repair" in the menu above

I didn't change any feature. It worked smooth and created a file named samename_repaired.sdltm
in the translation memory folder

This new TM file could be opened in SDL Trados and exported as tmx, then the tmx imported in a new sdl tm.
Maybe it was not necessary to export and reimport the repaired tm.

Isabelle Queinnec 

A nice feature.  I'm pretty sure under the hood it did carry out a similar sequence of activities, but probably considers more of the database.  Did you notice if anything was missing?  The metadata for example?

I'm not being critical... just very interested to know as this is a very useful option for anyone suffering with a corrupt TM.

Isabelle Queinnec 

ok - I tested both the personal and pro trial editions.  Only the pro version offers this and it does seem to do a decent job.  Thank you for sharing this information as I think it'll be very helpful for other users, and also us!

You're welcome Paul  :-)

I didn't notice anything missing. My translations seem to be all there. I checked some of them.
How can I see if metadata is missing and what are metadata?

Isabelle Queinnec 

Isabelle Queinnec said:

How can I see if metadata is missing and what are metadata?

Custom fields and their values, dates translations were created or moderated and who by, language resources... even things like the ability to recognise a context match as opposed to just a 100% match.  The SDLTM holds a lot of information so I wondered if you might notice if things are missing as you work.

I guess the most important thing is for you to be able to recover years of translating!!    Clearly it's already done a better job than our very basic repair tool does, but nonetheless if you do notice anything else doesn't get recovered it would be interesting to know the limitations.

Isabelle Queinnec 

Isabelle Queinnec said:

How can I see if metadata is missing and what are metadata?

Custom fields and their values, dates translations were created or moderated and who by, language resources... even things like the ability to recognise a context match as opposed to just a 100% match.  The SDLTM holds a lot of information so I wondered if you might notice if things are missing as you work.

I guess the most important thing is for you to be able to recover years of translating!!    Clearly it's already done a better job than our very basic repair tool does, but nonetheless if you do notice anything else doesn't get recovered it would be interesting to know the limitations.

Thank you Paul , I'll have a look at the metadata and will write here if I notice something is missing. I created the TM with the default options and didn't add any metadata myself. So the tm is quite simple. I'll check and report :-)