We have a number of XP Pro systems where we share C: with no problems. Most are using Trend Micro Internet Security.
One of them is a laptop using Zone Alarm and it has this problem:
Share C: for use in the office.
Everything works fine.
Take the computer home and connect to the home network.
(I don't know the Share status of C: at this point)
Return to work / connect to the office network.
The Share on C: has disappeared and has to be re-shared for it to work in the office.
Why a computer should lose a file folder share, even C:, seems very odd.
If you have experience with this type of problem then I'd like some guidance.