Cannot use pyflakes on Windows

[matrdr]

I tried using pyflakes with ALE. I installed pyflakes using pip and I can lauch the pyflakes.exe executable perfectly fine from the command line. But within vim ALE cannot use it.

:ALEInfo tells me the following:

(executable check - success) pyflakes
(finished - exit code 1) 'cmd /s/c "''pyflakes'' ''C:\Users\Matthias\AppData\Local\Temp\VYECD18.tmp\acg.py''"'

<<<OUTPUT STARTS>>>
Der Befehl "'pyflakes'" ist entweder falsch geschrieben oder
konnte nicht gefunden werden.
<<<OUTPUT ENDS>>>

The error message is unfortunately in German as my Windows is set to German, but it claims that "'pyflakes'" could not be found. What is interesting is that the executable check before succeeded.

Trying to type the same command to the command line results in the same error message. After some experimenting, I came to the conclusion that it might relate to the way the quotation marks are used here. When removing the double quotes, the command does execute.

[matrdr]

Ok, it seems like this problem occurs when PowerShell is set as the default shell in vim...