Epub to AZW3 conversion failure

[trampas]

I am running the 64 bit latest version of Calibre on Windows 8 and have found that if I try to convert more than one book at a time I get the following error (from the event viewer):
Faulting module name: QtGui4.dll, version: 4.8.3.0, time stamp: 0x50a06c97
Exception code: 0xc0000005
Fault offset: 0x00000000000a2e4f
Faulting process ID: 0xee0
Faulting application start time: 0x01ce0d1d44d2cd68
Faulting application path: C:\Program Files\Calibre2\calibre.exe
Faulting module path: C:\Program Files\Calibre2\DLLs\QtGui4.dll

Access denied somewhere I guess. If I do one book at a time than the process works fine. The conversion is epub to AZW3, to Kindle Paperwhite, with the 'insert metadata' option.

Superb program btw.

[kovidgoyal]

http://manual.calibre-ebook.com/faq....s-occasionally

[trampas]

Okay, as per your suggestion, I started Windows 8 Pro 64 bit in safe mode and tried again. This time Calibre 64bit just crashed. I have uninstalled and then installed various versions of the 64 bit Calibre with the same result.
However ... I installed the latest 32 bit version of Calibre, tried the conversion of two epubs to AZW3 and it worked fine. I then deleted the AZW3s and retried with the 64 bit version and it failed again with the original exception (post 1). So for converting two epubs, the 32bit version works fine but the 64 bit does not.
Of course, I can happily continue running with the 32 bit version now that I know, but if you want me to do any more tests then happy to oblige.

[kovidgoyal]

Then I suggest you use the 32 bit version.