Good day all,

I stumbled onto something recently while doing large amounts of file transfers due to clearing HDDs to change from NTFS to EXT, and rebuilding my small media server.

I came up against this slow file trash problem that has been talked about many a time since 2009. I did some of the "fixes" like clearing ~/.cache and deactivating the size limit in Dolphin preferences but it didn't appear to change anything.
My system: Arch with KDE.

I have a really slow drive on the system (a low capacity spare), and at one point thought that was the issue, but it wasn't listed in the trash settings, but to be sure I unmounted it.
By chance I came across a reddit post where one user recommended using another file manager, and as my deletions were taking about 15 seconds / 40mb file with 800+ to go, I was willing to try anything, so I tried another file manager as recommended by him that was present in my distro's files (not sure on moderators opinions on recommending alternative file manager packages outside of KDE so I'll just type the first few letters: PCMa....). I used the QT version as that was recommended, and low and behold I was able to move things to the trash quite quickly, but thats not all...

In Dolphin at starting this process, my trash was empty, no files, no hidden files, nada. After deleting the remaining 300+ files, I checked again and yep they were in the trash folder. When I checked the trash folder in the alternative file manager however, there were about 20 directories extra there that were deleted ages ago (3+ months previous), and I knew contained lots of files (only the directory was showing) and a couple were upwards of 40GB in size (Previous compiled copies of the Unreal Engine for Linux).
I was surprised, and so I figured, I would "empty trash" on the other file manager. It took about 3 minutes to empty, and after finishing. I tried to trash a 100Mb file in Dolphin as a test - it was instant!

As further tests I emptied the trash and checked the alternative file manager - empty also. I thought perhaps it might be large folders deleted at once with lots of contents (250K files, folders etc. 90GB) - another Unreal Engine compile, trashed the folder, and it was completed in 5 - 6 seconds, emptied trash, and it was gone in about 10 - 12 seconds - checked the alternative file manager - trash was empty...

What could be going on? - not sure what could be the cause of this, there seemed to be nothing special about the "residual folders" but for certain the total size combined they were above my limit on the Dolphin Trash capacity setting, and could have been the cause of the really slow trash operation (disabling the setting might fix it temporarily but depends how much "residual" is sitting there invisible).
Unfortunately I didn't think to take screenshots at the time, but hopefully this experience might help others that encounter this issue, perhaps it might lead to a reason and a fix?

Thanks for reading.

Pete