Version 3.4 is slow to Save, and it is easy to quit the program before the process is complete. This is made easier to do accidentally because the activity indicator for the Save process disappears if the cursor is moved away from the Save button, making it seem as though the Save process is complete. The lock files (.LCK and .LNK) a large .LOG file (96Kb, even when no substantial change has been made) and a binary file named something like: MDH.gnucash.tmp-gkUdOJ (where MDH.gnucash is the working file) are left, but there is no evidence that Gnucash has crashed. The large .LOG file contains numerous apparently redundant Begin and Rollback lines, which may be the reason for the slow Save. Before I switched to 3.4 I used 2.6.16, which typically produces log files in the 2k to 20k range.
I can reproduce this, including the rollbacks of the scheduled transactions in the logs. FWIW, the "activity indicator" that you're referring to is the busy cursor which indeed disappears if you move it out of the GnuCash window. That's reasonable, the desktop isn't busy. The actual progress bar in the lower right of the GnuCash window works fine.
Found it, an improperly-thought-out if condition in the MacOS-specific quit function. The fix will be in GnuCash 3.5.
