After upgrading to Windows 7 on my laptop I found that I could no longer sync with my Sony Ericsson X1 (Windows Mobile 6.1) Phone. It didn’t even seem to be charging (over USB).
Looking in the system Device Manager I found a missing driver for the ‘Generic RNDIS’ device.
A bit of goggling uncovered that this was something required for syncing mobile devices. Although there are comments around that Windows Mobile devices are not supported on Windows 7 beta, and a number of people seem to be having the same problem, the good news is it does actually work.
I simply downloaded the Windows Mobile Device Center 6.1 for Vista (from Microsoft), installed it and everything was rosy.
It installed the driver for the ‘Generic RNDIS’, I connected the phone, it was recognised a Microsoft USB Sync device was installed and it all started working as expected.