AdiIRC

As posted on #adiirc @ chat.freenode.net: 16:19:41 <Koragg> $disk total $disktotal - $diskfree free <--- $diskfree actually shows the used up storage, not the storage that is free (using the built-in AdiIRC identifiers)

Discovery by using the built in System Info option from the channels menu (in there Harddisks) and comparing to properties of my C: drive in Windows Explorer:
[16:26] <AwayLurker> DISKS: total 296 GB - 137 GB free
Another issue is that the total diskspace according to Windows Explorer is 223 GB and NOT 296 as AdiIRC assumes in $disktotal
I will attach a screenshot showcasing the actual numbers (system language is German, so it would need to be potentially translated by others)

The OS is Windows 10 and AdiIRC version is is the Beta 3.9 dated 17th of April 2020
As I only have AdiIRC installed on Windows 10 devices I am unsure whether it applies to other versions of Windows or e.g. Linux as well.