ACCELERATE A SLOW-OPENING MASSIVE EXCEL FILE My work requires the use of several very large Excel files, and they take forever to open. In fact, they even take a long time to save and close. I’ve ...

Select the .dat file you want to open in Excel. Finally, in the Text Import Wizard that opens up, select Fixed width, and then set the Field width and Data format when asked. How to convert .dat ...

If the DAT file you're trying to open is text, you can convert the file into text in the Microsoft Excel program by first saving it as a CSV file. Right-click the DAT file on your PC and click "Open." ...