I was having a problem whereby when I plugged my G1 into my Vista machine, it would not mount so I could not retrieve files or download pictures. I found this useful walkthrough which fixed the problem. Basically the problem is that the computer is mounting the device as an HTC dream as opposed to USB storage. Original Post here:
Finally, I got it work on my vista ultimate.
Here is what I do, hope it can help.
1. Just as lots of people mentioned, I did not see removable disk showing in Explorer after I connect G1 to computer. Even I tried mount on the phone, it still doesn't work.
2. Then I go to Device Manager, I don't even see any USB Mass Storage Device at all un Unversal Serial Bus controllers.
3. Because I know the device is connected, I decide to expand all the devices. Immediately, I notice there is a device called HTC dream.
4. We all know G1 is HTC and but it is recognized as HTC dream device rather than USB Mass Storage Device.
5. Now let's change it back to USB Mass Storage Device.
6. Right-Click on the device (HTC dream), select Update Driver Software (it is the first menu item).
7. Do not search automatically, click the second one (Browse my computer for driver software).
8. In next pare, choose Let me pick from a list of device drivers on my computer.
9. Now you will see two drivers are listed (select check box for Show compatible hardware)
10. Select USB Mass Storage Device and click Next.
11. After installing, now removable disk is shown in explorer.
12. When try to open the disk, it will ask you "Please insert a disk into Removable Disk".
13. Back to you phone, from notification bar, mount you sd from USB connected.
14. You can open to browse you SD card from your computer.