Microsoft Office provides a feature called AutoSave to help you avoid the catastrophe of losing work because your computer crashed or because you forgot to save it before closing the application. It's only available in Office 365, the subscription version of the software suite that includes access to Excel, Word and PowerPoint. If you have an earlier version of Office, the AutoRecover feature can be used to recover data when an Excel document is not saved.
AutoSave in Excel
When the AutoSave feature is enabled in Office 365 applications, the current file will be saved automatically in the background every few seconds. For files stored in the Microsoft Cloud on OneDrive or SharePoint Online, AutoSave is enabled by default. If AutoSave is grayed out, it's probably because the file is being saved to some other location instead of the cloud, such as to a file server or to a local directory like Documents on a desktop computer or laptop.
If you are an Office 365 subscriber and have the most current version of Excel installed, you can see whether AutoSave is turned on by checking the upper-left corner of the application window. The AutoSave toggle will be shown as either On or Off. To make changes to a file without having them saved automatically, simply move the toggle to the Off position. You can then use Save to save changes at your convenience.
AutoRecover in Excel
In Office 2016 and earlier versions that don't support AutoSave, the AutoRecover feature can be used to recover an Excel file after the application has shut down before the current file could be saved. When Office applications detect that a crash has occurred, the Document Recovery dialogue is displayed the next time the application is started. The dialogue lets you chose to save or discard recovery files that contain unsaved data. The date and time when the recovery file was created are displayed next to the file name to help you decide if you want to recover it. You can also open any file in the list and review it before saving it.
The amount of data that can be recovered from a file through AutoRecover depends on how often information is being saved. You can control this and other AutoRecover settings from the Options menu on the Files tab. Under Save, you can toggle AutoRecover file saving on or off and specify how often recovery information should be saved. You can also specify whether the last autosaved version will be saved after you close Excel and where the recovery file should be stored.
If you don't want to lose much work due to an application crash, you should set the minutes interval for saving file data to a low value like five or 10. There is a performance tradeoff, however, since the application may pause briefly while the file is being saved. If performance is more important than saving data, then set the interval to 20 minutes or longer.
AutoSave Issue with Save As
Some people create a new Excel or Word file that is similar to an existing file by opening the existing file, changing it and then using Save As to save it with a different name from the original. A problem arises when you enable AutoSave. Changes made before you used Save As will be automatically saved to the original file, which may not be your intention. Microsoft recognizes this problem and has replaced the Save As command with Save a Copy in Office 365 applications. It's recommended that you use this command to create a similar file before you make any changes to the original in order to circumvent the AutoSave issue.