Until recently, the epocrates website had stated that it was not compatible with vista syncing (i.e. windows mobile device center). They have recently updated their support page to say that it DOES in fact work now.
It did not, however, work for me when I deleted everything and re-downloaded the software and attempted installation. I sent a support request email to them and they promptly replied with the following:
Try the following to get the software working. We created a new installer that now works with Vista.
Uninstall Epocrates from your computer in the control panel while the device is disconnected.
Delete any installers that are saved on your computer.
Once that is complete, proceed to remove any Epocrates files from your device by following the steps below.
A. Delete Epocrates from the device
1. On the device, open Start>Programs>File Explorer.
2. In the drop down list at the top, select My Device.
3. In the list, look for any files that begin with Essentials or Epocrates, and hold your stylus down on the name of the file. Select Delete. (You may not have any of these files, so move on to the next step)
4. From the MyDevice directory, select Program files. (Right below the words "File Explorer, drop the menu down to find "MyDevice")
5. Delete the Essentials folder. (Hold your stylus down on the word Essentials and select delete.) Also, delete the folder called Rx Pro if you have one.
6. Close the File Explorer.
7. On the device, click Start>Settings>System (at the bottom) then Remove Programs
8. Remove ALL Epocrates items in the list.
B. Soft reset your handheld, and leave it disconnected from the computer.
C. Download a new installer on our website. If you have one on your desktop already, please delete it.
1. Return to our website (www.epocrates.com).
2. Click the "My Account" button at the top right corner of the page.
3. Log in.
4. Click the "Download" link to the right of software you would like to install. (If you are a free user, click the Download button in the center of the page.)
5. Select your memory options if prompted, and continue.
6. Click "Begin Download" and RUN the file.
7. When prompted, connect your device with the cradle or cable, complete the install.
I did all of this with still no luck. I continue to get the following error during installation: "Device not detected or logged on as Guest" - however, neither of these things should be issues. The device is actively connected with my mobile center and I'm not logged as a Guest. If anyone has had a similar experience or any advice, please let me know. Thanks!