Yes, if it's already been converted, it's too late - the original full text that was in the paste buffer or the automatic import from the .csv file that your us

Yes, if it's already been converted, it's too late - the original full text that was in the paste buffer or the automatic import from the .csv file that your user just blindly double-clicked is gone. But no, if you first set the formatting of the destination cell to text and subsequently paste in your data, it won't do the conversion. If you're using a Data->From Text/CSV Power Query import that establishes a persistent data source, well, fix your import so that it sets the proper formatting on the destination. But that requires changing the defaults, and given the stickiness of defaults and the number of Excel installs anything that's not the default is going to result in data loss. This does establish global preferences that a system administrator at your college or workplace can change to protect users from themselves. I wish it was the default for new Excel installations, but that's not how they did it.