This is a USA issue (these parts have only ever been in the US library).
Graphisoft US (not HQ in Hungary) did this for totally unknown reasons - just as they also only provided a 'commercial' template out of the box this year, rather than residential and commercial as in years past.
Contact your reseller to complain.
The workaround is to use the File > Libraries and Objects > Extract a Container command on the AC 20 library LCF file to temporarily unpack the entire library into some folder (maybe call it AC 20 Detailer Lib) on your computer where you'd like to keep these symbols for future reference.
Remove everything from this folder EXCEPT the 00 General 20/Detailer Library 20 folder as well as the MACROS 20/Detailer Macros 20 folder. You'll remove more stuff in a bit.
If you want all of the missing 2D symbols, open Library Manager and add the folder above (AC 20 Detailer Lib or whatever you called it). You'll get a ton of duplicate part error messages because of the selected symbols that ARE in the AC 21 USA library. You can later eliminate those errors (you should) by going to the folder you created above and deleting the folder/content that corresponds to what IS in the AC 21 library in the 00 General 21 > 2D Details 21 folders. Crazy, but you'll see that while the original library has all kinds of masonry, the Masonry 21 folder only has what is in the CMU folder from the old library - so just delete the CMU stuff from the disk folder that you created. Etc.
After clean-up, the folder on your disk will contain all of the old stuff that isn't in the new 2D Details 21 folder. I have no idea if they improved any of those parts or why they chose to only include the random folders that they did.
Karl
AC 28 USA and earlier • macOS Sequoia 15.3, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB
One of the forum moderators
