There are several issues or conflicts that can occur in a roaming profile environment that basically come down to administrative questions.
Most items stored on the desktop or in the Start folder are shortcuts, so if the different PCs that the user is logging on from aren't set up the exact same way (installed programs, folders, etc.) then the shortcuts may not be valid, and you may see a series of invalid shortcut errors when you log on in these situations.
For the same reason as above, it's best not to mix and match different Operating Systems for the same user. Windows 98 and Windows NT profiles can co-exist in the same profile folder on the server; however, because different types of information are stored in each case, you may see inconsistencies; particularly if the profiles are not mandatory.
If the same user is logged on to the same Logon Server from different clients, user profile info is saved independently during logoff for each. So, the last one to log off will reflect the actual changes saved to the profile.
You may see the message, Your roaming profile is not available. You will be logged on with your local profile. This typically means that the roaming profile could not be found in the expected place. See Configuration from Windows 2000 and Windows XP clients for information on copying a user profile to the server.
The error may also indicate that either the configured roaming profile folder is not shared or the integrated file system directory permissions do not allow access.
Users may, inadvertently or not, store files other than shortcuts on their desktop. If these files are very large, it can significantly slow down the logon process. A workaround is to specify certain profile subfolders not be included in the transfer between Logon Server and client.