User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36 Steps to reproduce: Have imap mbox folder structure of aprox. 3.96GB Set preference mail.store_conversion_enabled Change message store type to maildir in Account Manager/Settings Actual results: Conversion dialog appears with progress stopping at 71% Error console reported: Error: [Exception... "Out of Memory" nsresult: "0x8007000e (NS_ERROR_OUT_OF_MEMORY)" location: "JS frame :: resource:///modules/converterWorker.js :: <TOP_LEVEL> :: line 162" data: no] Expected results: Completed the conversion.

I have the same issue. But mine stops at 0% since it is a super huge e-mail account. It worked for smaller accounts. It is POP3 not IMAP. TB goes straight to 2GB and then the error appears in the console. A 64bit version may work or something else must be done. Since Console2 and other stuff is not available I can't tell on which folder it failed.

probably same issue as bug 1491228