Pavla Voltrová

Well... I think my initial thoughts would be that you may not be looking at the TMs you think you are.  Back in the days of Studio 2011 we used to create Project TMs by default so perhaps you have a lot of TMs all over the place and didn't realise?  Many apologies for the newbie sort of question but  don't know how familiar you actually are with Studio despite having started in 2011 at least.

Maybe run a search on your computer for *.sdltm and you "might" be surprised at how many TMs you have.  Also double check that the TM in 2011 which contains matches you expect is actually the same TM as the one you are now looking at in 2021.

Thanks Paul, this helped! The most up-to-date memories were actually hidden in some random folders inside the old 2011 projects, so I imported them one by one into the new projects. Thanks again!!