sdu extension on my qb 2017 business files. How to open them?

Good evening, @cdc53. 

Welcome to the Community. I hate to hear that your computer crashed and now your QBDT companies have an sdu extension. 

Based on the details you gave, we recommend speaking with your IT or an IT individual so they can look into these extensions and help you change them to the proper files. 

Feel free to reach back out and let us know how it goes. We're always here to have your back. Take care! 

@cdc53 

Did you ask someone else to restore data from the crashed computer?