I have an Excel file but am not sure if I can trust it. Is there any way to figure out if it would be safe to open it? If not, is there any way to see a preview?
Assuming you are going to open the Excel using Calc, otherwise you should be posting in an Excel forum.
Before opening the file, open Calc on your system and check under Tools, Options, expand LibreOffice and select Security. Click on “Macro Security…”. Make sure security is set to at least Medium.
Then if you open a file with macros you will get a warning and you can disable macros. You can then view the macros embedded in the file and see what they try to do before re-opening the file and enabling macros.
If the macros are complicated or you don’t understand them it might be better to leave them disabled.
If you need to try the macros without risk to your computer then consider using a sandbox or virtual box to test the macros.