I also reinstalled LR 5.4, without any problems. I then tried the same synchronization again in LR 5.5 and to my surprise, it worked as it should. Uninstalled 5.4 again and tried 5.5 sync - this time no problem. However, on closing LR, got an error message in regards to Media Server. The Application Event lists the following:
Faulting application name: Adobe QT32 Server.exe, version: 7.0.1.0, time stamp: 0x52318f02
Faulting module name: QuickTime.qts_unloaded, version: 0.0.0.0, time stamp: 0x52d49206
Exception code: 0xc0000005
Fault offset: 0x60aacd89
Faulting process id: 0x9c
Faulting application start time: 0x01cf91fd6c0a7875
Faulting application path: C:\Program Files\Adobe\Adobe Photoshop Lightroom 5.5\Support\DynamicLinkMediaServer\dynamiclinkmediaserver\1.0\32\Adobe QT32 Server.exe
Faulting module path: QuickTime.qts