Ok so there seems to be no real set in stone answer on this question.
How man files can fit in each folder?
DWA FOLDER
GRAINS FOLDER
WAVS FOLDER
Rumor has it that it’s 250 files per folder only, but would be nice to know for sure from someone at polyend.
This information should really be in the manual as well.
The official and definitive answer is: 256 files per sample folder.
Really? I did some tests a while ago, and @mitch confirmed it’s 250:
May be a typo then? I have the information directly from the developers and specfiically asked for file limits for samples.
So maybe the limits are different depending on what they are for?
Only way to have certainty i guess is to try it for ourselfs 
Definitely no typo, because I had discovered a limit of 250 for scenes and reported that as a bug (manual said it’s 1000), and Mitch replied to that.
That’s possible, but odd, it was described as a issue related to the filesystem. I think I confirmed that limit for for samples, too, but I don’t remember exactly. But it’s simple to test, will test that when I find some time.
Thanks for the info! However I do not like this… Should be based off the size of the SD card.
I tested it again for Scenes, samples (GRAINS, WAVS, DWA) and patches (ACD).
I also found out why I previously found only 250 scenes: entries are read in the order they have been added, not alphabetically.
I wonder something and probably not but…
So if we can only read 256 in a GRAINS/DWA folder and 256 in PATCHES folder etc..
Could we make more than one version of each folder with different content in each and it would read?
Like have 3 DWA folders filled with 256 of different samples in each, which would it read from… or would it just read from all 3 at the same time or read all 3 and just pick one when it boots up etc?
If they want to set limits on content inside folders, then they should allow us to be able to make duplicate versions of each folder as many times as we want with different content in each, and allow us to pick which one for synth to use.
For example if we’re using DWA engine and we go to the sample section, soon as we turn the sample knob it would read from the sd card and bring up all DWA folders that we can choose from. Same goes for GRAINS/WAVS…
I don’t think anybody wants that, it’s just a constraint of the file system itself, or of the code that addresses the file system.
However, there is already a wish that would free us of that constraint of 256 samples per engine, and without taxing the Synth’s memory or CPU, because it would only require a change in the code for browsing the samples (or presets), and of course a few more bytesfor storage of longer filenames inside the presets and scenes.