Hi Thierry Kumps

You can update a TM from the Translation Memory view of Studio so you don't have to open each individual project.

Unless the TM is already in your translation memory list on the left pane of the Translation Memory view, open the TM via Open.

You can close it then highlight it in the left pane.

Highlight it in the list:

Then either select Import from the top toolbar (highlighted above) or right-click on the translation memory and select 'Import' from the dropdown menu.

Then you can add as many target SDLXLIFF files as you want to run one import operation. Select SDLXLIFF files individually by naviguating to each project's target language folder or just add each target language folder.

The software will only find and import SDLXLIFF files in the folder selected but you MUST be sure it's the target language folder not the source language folder or the language direction of imported segments will be the wrong way round...

The above is the 2019 import wizard but doesn't look much different to the 2017 one.

Thereafter it should be obvious what settings to use but come back and ask if it isn't.

Hope this helps!

All the best

Ali

The problem is that Import is missing the "Merge" option present in the Update!

So I would rather manually - using some smart file manager which can search for files across folders and then let you select from the found files and copy them to other place - copy the bilingual files for each language pair from all projects into a single folder for each pair (hoping that there won't be many filenames clashing, so that I won't get mad from too many renamings) and then create a temporary project using these bilinguals and use it to update the TM.

Unknown said:

I've found that 'Add new translation units' when importing actually does also overwrite existing TUs with different target content, which is what I presume 'Merge...' means.

Actually not, it means something else: https://docs.sdl.com/LiveContent/content/en-US/SDL%20Trados%20Studio%20Help-v4/GUID-7FFA2DD3-7CDE-4106-AE7E-4D25C2D67943
See also this KB article: https://gateway.rws.com/csm?id=kb_article_view&sysparm_article=KB0028019
The "Merge" option was added in Studio 2015 SR1.

"Add new TUs" should definitely NOT overwrite existing TUs!
You may be referring to a bug introduced in Studio 2014 SP2 CU9 where the TM Update batch task default action was "Overwrite" instead of "Add new" (remember, the "Merge" option did not exist yet)... and many people didn't even notice... The bug was then fixed two months later in CU10.
Someone wrote a number of blog articles about this problem back then with more details, but I forgot where it was and can't find it anymore...
Found the blog articles:
http://cat-tool-translation.blogspot.com/2015/08/sdl-studio-cu8-conflict-between-update.html
http://cat-tool-translation.blogspot.com/2015/08/sdl-studio-cu10-update-translation.html