The plugin as a limit of 200 files of unclustered files to process, anything above that gives the error "Could not calculate replaygain".

Log error: 

E: 17:08:02,111 picard\util\thread.run:114: Traceback (most recent call last):

File "picard\util\thread.py", line 111, in run

File "C:\Users\texlo\AppData\Roaming\MusicBrainz\Picard\plugins3\replaygain_2_0_74807b76-c451-419f-bbd4-42a78e2444a6_init_.py", line 211, in calculate_replaygain

with subprocess.Popen( # nosec: B603

~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^

call,

^^^^^

...<4 lines>...

text=True,

^^^^^^^^^^

) as process:

^

File "subprocess.py", line 1039, in _init_

File "subprocess.py", line 1553, in _execute_child

FileNotFoundError: [WinError 206] The filename or extension is too long