After my testing, it seems that the crash is coming from HFS.ini "recent=" line.
For example:
If the line were filled with "C:\HFS\VFS.vfs" (w/o the quotes)
then HFS will not serve pages + it will cause AVs when you try to close it.
Clearing this line will remove this crash and HFS will work normally.
But right after you close it again, HFS will write that value back into the INI file therefore HFS will froze+crash again after you reopen it.
Good Luck fixing the bug!