How does one abort subject command?
+ Click the Abort button in the small "DXKeeper Update from LoTW" window that should be present on your monitor.
I had never run it before and have over 100,000 QSO's in my log.
+ Invoking "Update from LoTW" with more than 1000 QSOs in the Log Page Display displays this message:
"depressing CTRL while clicking Sync LotW QSLs will certainly be faster"
+ and gives you the opportunity to immediately abort the operation.