When having ArcGIS Maps for Office as an active add-in, the date format set in the system settings is not honored when exporting from Microsoft Excel to a tab delimited text file format.
Click the File > Options. Select theAdd-Ins category.
In the Manage box, click COM Add-ins > Go. The COM Add-Ins dialog box appears.
In the Add-Ins available box, clear the check box next to the add-in that you want to remove. Click OK.
Note: This workaround removes the add-in from memory but keeps the name in the list of available add-ins. It does not delete the add-in from the computer.