My wife and I share a dropbox account to keep our photos synced across devices.

This has always worked perfectly well but after the missus added some photos to dropbox on her comp, I am suddenly getting this error:
Code:
Can't sync [numbers].JPG: permission denied
My dropbox contains the folder she added but none of the photos inside and my computer is grinding to a halt until I turn dropbox off altogether.

Only thing I can think of is that my dropbox folder is on an NTFS partition, though it hasn't caused any problems before.