Hi Matthew,
By any chance, is your "My Documents" folder on a network share? If this is the case, then you cannot use the shared settings for WIM that are stored in TFS source control because TFS cannot map source control workspaces to network folders.
To check if you are using shared settings, click the application button in the top left corner of the app and then click Options. If the "Use Server Settings" box is checked for your current project, try unchecking it and then try saving the iteration schedule again.
The downside to not using shared settings is that some things such as the iteration schedule, task board settings and dashboard settings are not shared with other team members and are only local to your machine. This can result in a disconnect between team members because they may not be looking at the same information.
If you are still having issues after trying some of this suggestion, please check the WIM log file for any errors and post the errors here. The log file can be found at {My Documents}\Work Item Manager 2010\WIM-log.txt.
Regards,
Joel
the Telerik team
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