General file corruption problems:

Follow these instructions to fix this problem:

1. Open your file and choose Edit | Select | All.

2. Choose Edit | Copy and select all the options.

3. Choose File | New | Normal.

4. Delete all the tracks in this file.

5. Choose Edit | Paste.

This should alleviate the problem that you are having.

Otherwise, if you are using SONAR 2, you can hold down the Shift key while opening the file under File | Open in SONAR. This will allow you to load the file without the plugins in-case any of them are corrupted and causing the file not to open.