I am experiencing the exact same issue as doteddy. Additionally, I am not able to sync an iPod on any account other than the first account that is logged in.
- Boot Win 7 64 bit;
- Log into Account "A";
- I can access iTunes Preferences and sync an iPod Touch without any issue;
- Close iTunes in Account "A";
- Switch User and Log into Account "B" (note Account "A" is still logged, but I have switch over to using Account "B";
- I am unable to access Preferences in Account "B" and I am unable to sync an iPod on Account "B";
- Log out of Account "B";
- Log out of Account "A";
- Log back into Account "B";
- Now that I am only logged into Account "B" I can access Preferences and Sync the iPod Touch on Account "B";
I have spent five hours trying to resolve this issue, unsucessfully. I have tried many solutions suggested by others with similar problems, but to no avail. I have uninstalled, reinstalled, and repaired iTunes several times. I have also tried creating new user accounts and using alternate accounts. The problem doesn't seem to be associated with specific user accounts; rather it is associated with being logged into more than one account simultaneously.
The problem is fully repeatable on my Win 7 64 bit system with iTunes 10.6.1.7 installed.
Note: the accounts that I am using (i.e. account "A" and account "B") have different security privileges. While I don't think this is material to the issue, I mention this just in case.