"Some Power BI Desktop customers using the February release may run into “We weren't able to restore the saved database to the model.” error while opening the PBIX file. Engineers are investigating. As a mitigation, customers can use December release of the PBI Desktop that can be installed from here: https://download.microsoft....
If you experience this issue and can help us troubleshoot it, please reach out to alexgor@microsoft.com. Thanks!"
Good luck!
Danny