I don't know how NodeXL's template file (that's what "NodeXLGraph.xltx" is) can become corrupted, assuming you didn't modify it after installing NodeXL. I'm wondering if Excel is giving a misleading message, or if there is something wrong
with your copy of Excel.
Please try the following:
1. Go to "Test files for Cannot open NodeXL after installation" on NodeXL's Issue Tracker tab on CodePlex. It's at
2. Download the NodeXLGraph.xltx attachment under the "File Attachments" section. Save the attachment somewhere on your hard drive. This is just a copy of the NodeXL template. I know for a fact that this copy is not corrupted.
3. In Windows Explorer, double-click the file you downloaded.