When quitting Kleopatra it always crashes. You need only to start Kleopatra and close it again, no additional prerequisites.
This is debugview log starting from clicking "Quit":
0.000000 2024/10/31 09:36:17.417 4968 kleopatra.exe org.kde.pim.kleopatra: 0.044631 2024/10/31 09:36:17.462 4968 kleopatra.exe org.kde.pim.kleopatra: ReaderStatusThread[2nd]: new iteration command= "__quit__" ; nullSlot= true 0.052012 2024/10/31 09:36:17.463 4968 kleopatra.exe Please call QDesktopServices::unsetUrlHandler() before destroying a registered URL handler object. 0.052012 2024/10/31 09:36:17.463 4968 kleopatra.exe Support for destroying a registered URL handler object is deprecated, and will be removed in Qt 6.6. 1.300210 2024/10/31 09:36:18.703 4968 kleopatra.exe <process started at 09:36:01.399 has terminated with 0xc0000005 (EXCEPTION_ACCESS_VIOLATION)>
Here are parallel logs from debugview and gpgme, both from start to quit: