[KevinH]

FYI: If the crash is associated with file open dialogs or file selection dialogs it is almost certainly caused by a Windows third party file or shell system extension you have in your system or a bad usb device driver. Many of these third party system shell extensions do not properly protect/hide the older Qt version they are linked with and so cause crashes when loaded into memory with newer Qt using software. That calibre faq link lists a number of known bad shell extensions.

Try reading and checking if you have one of those bad third party shell extension installed. Some are default installed by the computers manufacturer, not Windows.