Error: "The file is corrupted and cannot be opened."
Immediate Recovery Steps
1. Open and Repair
Open Excel (blank). Go to Open > Browse. Select your file (single click). Instead of clicking "Open", click the small arrow next to it and select "Open and Repair".
2. Extract Data Only
If repair fails, try selecting "Extract Data" in the repair dialog to at least get your values and formulas back, sacrificing formatting.
3. Calculation Method
Set calculation to Manual (File > Options > Formulas) before opening the file. Sometimes the crash happens during the recalculation phase on open.