One or more parameter values are not valid” error message when you create/update a task in Outlook
When you attempt to update a task in Microsoft Outlook, you may receive the following error message:
Could not complete the operation. One or more parameter values are not valid.
CAUSE
The Microsoft Exchange Server mailbox, or the Tasks folder on the server, is corrupted.
RESOLUTION
Choose one of the following methods to correct this problem. The methods are listed from easiest to most difficult. The first method, if successful, does not result in data loss. The second method results in the loss of task data. Method 3 may result in significant loss of data.
Method 1
1. Open your Task folder in “Simple List” view.
2. On the Actions menu, click Save Task Order.
NOTE: Because the “Save Task Order” function can only be applied to a non-filtered view, you must have the current view set to “Simple List” or “Detailed List”, and in the default views.
Method 2
This method assumes that you have a copy of the old Exchange Client 5.0 that shipped with Windows 95 or Office 97. Search your hard drive for exchng32.exe to confirm its presence before proceeding.
1. On the File menu, click Exit and Log Off.
2. Click the Start button, click Run, type exchng32.exe in the Open box, and then click OK.
3. Delete the Tasks folder from your mailbox, and then click Exit and Log Off on the File menu.
4. Click the Start button, click Run, type outlook /resetfolders in the Open box, and then click OK.
This method deletes and recreates the Tasks folder, without affecting any of the other folders on your mailbox.
Method 3
Quit Outlook and have your server administrator remove the mailbox on the server, and then create a new mailbox.