Importing large Mendeley database


I am trying to import a large Mendeley database (~40,000 references, 195 MB) into Zotero. The Mendeley version is 1.18 (i.e. before encryption) and Zotero latest version.

I follow the recommended steps (File -> Import -> Mendeley) choosing 'Link to files in original location'. After importing ~300 references each time, I usually get an error 'Zotero has stopped working', or new references just stop being added without receiving any error. I have tried running the import process in two different laptops with 8 and 16GB RAM (both on Windows), but every time I only managed to import 200-300 new references.

I have managed to import ~20,000 references so far into Zotero by running the import process many times (in chunks of ~300 references each time). Importing the other half of the database will take many days, so if anyone has any advice on how to smooth or speed up the process, I would be very grateful to hear.

Thanks and best wishes

  • edited March 7, 2021
    If you check RAM usage in Task Manager, is Zotero getting up to 3 GB of RAM before it stops? If you open Help → Debug Output Logging → View Output, does it stop logging when it stops? If you're able to take a screenshot of the end of the output (assuming you can't copy it) and email it to with a link to this thread, that might be helpful. (Make the logging window as big as possible before starting so you capture as much as possible.)
  • @Pakillo: Sorry, can you actually try redirecting output to a text file and emailing us a zip of that after an import attempt instead?

    See Logging to a Terminal Window, but use -ZoteroDebugText > file.txt (which I've just added there) instead. That should create a file.txt with complete output in whatever folder you run it from (probably C:\Users\[username] by default).
  • zotero(3)(+0000001): User interface ready in 600024 ms
    There seems to be a more general problem with Zotero's disk access on this computer. Just starting up Zotero appears to be taking 10 minutes, with extremely long delays for all sorts of basic database queries.

    Are these particularly old computers, 16 GB notwithstanding?

    Do these computers have spinning disks instead of SSDs?

    Was there some other sort of heavy system resource usage while you generated this debug output?

    It's fairly quickly processing thousands of existing items, but any time it has to touch the disk, it's extremely slow.

    You said via email that Zotero was indeed using 3 GB of RAM. Does the RAM usage increase during the import, or is it that high immediately after startup?
  • Hi,

    It took a few days, but I finally managed to complete the import using a more powerful computer and Zotero latest version.

    Many thanks @dstillman for the support
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