Unknown to most people it is possible to open Excel files in slightly different ways. Typically this is used when working with a corrupt file ( see Repair Corrupt Excel Files) but there are some other Excel Open As Options as shown below.
Opens your file. You use this every day
Open Read Only
Allows you to open the file as Read Only even if it is not set as such.Useful if you want to protect yourself from accidentally making a change.
Open as Copy
Immediately creates a copy of the file and anything you do is reflected on the copy and not on the original. Very useful when you are doing Data Cleanup and need to stick to the Data Cleanup rules on our Online Course
Open in Browser
Opens the file in your internet browsers. It needs to have been saved as such, so it is not always available as an option as shown above.
Open in Protected View
Similar to the Read Only option except if you do decide to make a change you can click the Enable Edit button and proceed, instead of closing and reopening the file.
Open and Repair
For files that seem to be corrupt. More detailed information available at the Repair Corrupt Excel Files post
Show Previous Versions
If Excel has some previous versions it will allow you to open them.