Importing PowerPoint Slides Hangs Indefinitely at Reading Until Crash

Storyline and Storyline 2 are now both, for some inexplicable reason, incapable of importing a PowerPoint (2010) presentation as a new scene/slide. Previously, this was only happening in SL2, but now the scourge has extended to the older and less shiny brother.

What happens:

This. Forever. When I try to "X" it out, nothing happens. When I try to close the program from the spinning wheel of death, nothing happens. I have to end the task every time.

So before you ask (because I did do my homework on this issue):

• Yes, the PP and SL files are on the same HDD — they're in the same folder.
• Yes, PP and SL are using the same permissions.
• No I don't have two versions of PP installed, and no there is nothing wrong with PP itself or the files I am trying to import (they open just fine in PowerPoint).
• Yes, both PP and Storyline (1 and 2) are updated to the current service pack and/or version.
• Yes, this happens with every single PP file I attempt to import, even a fresh file I make one minute before importing.

So what gives? This is a massive inconvenience and it was not happening a couple weeks ago. What changed?