If a P6 XER import is taking an extended amount of time then you are likely experiencing the dreaded POBS bug. Note that POBS data has never been used by P6. You became infected by importing an XER file containing errant POBS data. Once infected any future XER exports from your machine also spread the problem. Even after applying this fix you can be re-infected by importing a bad XER file.
The solution is twofold:
The results window at the bottom of the page will show you how many POBS rows were deleted. At this point your P6 is now clean and will remain that way UNLESS you import a corrupt XER file that you failed to run “POBS Cleaner” on. Try not to do that.
Enjoy your newfound import speed and good luck.
Note: This issue has been resolved for version 16 and above