An alert to an older thread on this issue suggested creating a new posting:
Sync is not working on Vista desktop interface for PRS 600.
Sync hangs on individual files even after
all suggestions in this older thread were carried out (remove from BEP list, uncheck various options in preferences, etc) except for choice manual sync option, which I cannot seem to find. Removing these files (books) from the library view results in Sync hanging on the next item.
I have also disabled AV blocking of autorun.inf on the device has been disabled (this may be a problem for some.
Sync runs in an endless loop. New purchases are added successfully, but multiple instances of purchased items cannot be deleted from the device (as explained in the documentation) and deleting them in the desktop library view does not impact the device content - desktop library shows 70 items compared to 91 books on device. (Issues with the Borders site resulted in multiple downloads).
Several books on the device do not show the synchronized icon. Some items in the desktop library view are marked by the "recently delivered" icon (red dot), which is apparently for periodicals.
I am able to find no information on this issue on the Sony site or elsewhere. Hopefully someone has new ideas on the matter. Note: using newest software version.