Conditional formats all gone

I spent hours putting in conditional formats. They all worked yesterday. I opened the sheet today and they are all white. The document keeps opening in safe mode. I had Libre un-installed and reinstalled. Still didn’t solve the issue.

I can open calc normally but this document I can’t. I had it saved a few different ways as back ups. Every single one opens in safe mode

I honestly want to cry. This is a huge project and redoing it is going to be terrible.

If I have to reapply condional formats I’m okay with that. Not wild about it but okay.
However I don’t want it to happen again! I’m trying to delete my hundreds of custom styles. None of them are deleting. I did F11. Right click and delete. They are staying on the list.

This spreadsheet is going to be used by hundreds of people weekly. I can’t have conditional formats not work or suddenly disappear.

At least four questions/topics:
-1- How to avoid files opening in “safe mode”?
-2- How may I have lost CF?
-3- How to delete custom styles?
-4- Can I probably find a previously saved version of a “destroyed” document?

Missing information (at least):
LibO version? Operating system? File “format” you saved to: alien or native? What message was shown to tell you “safe mode”? What message was shown when you tried to delete a custom style? Was it a named cell style actually?

Try torecover first from just feeling terrible, and sort your thoughts and questions. Someone may find a way to help you with one or another. Do not save anything to the files you have problems with. If a save operation is needed, change the file name usibg ‘File’ > ‘Save As…’.
Come back with split questions and clear completed information.

Sorry. I’ve saved the document as both ods and xlsx. It was fine in xlsx before. Now it is gone. I’m opening it in Libre. Is the the issue having the xlsx file extension? I’m in

The safe mode dialog box opened. I believe I finally got it to restore. Still, my conditional formats are there but all showing as white unless I reapply them. The colors are in the style but not showing up when I go to manage or open it later. I can just keep it in ods If xlsx is the issue