I saved a file from 3 days and now i am opening the file and they tell me that the file format is unexpected what should i do? tomorrow i should present this file please help me!!!
What version of SketchUp are you actually using? SketchUp Free (web) or SketchUp 2020 Pro? Your profile is confusing. What operating system? Please correct your profile and replace the nonsense answers with the actual requested information.
If you are using SketchUp Pro you might be able to open the backup file. You could share the .skp file so we can see what you’ve got and perhaps help you fix it.
I am using SketchUp 2020…Where do i share the file?
Please correct your profile. That information helps us help you.
Upload it here or, if it’s too large, upload it to DropBox or Google Drive and share the link.
Give me your email so i will send it via wetransfer
The way I try to recover files immediately fails with your one, which is unusual. Do you have a backup file, which would be in the same folder and the same name, only a .skb extension (if you are on Windows)?
No i delete the file with skb extension. There is no solution?
Why would you do that? That eliminates your chance at having a back up file in case of a problem.
Is it possible that the .skb file is in the Recycle Bin?
Please correct your forum profile already.
No i SHIFT DELETE 
the file … There is any solution?
Probably not at this point since, as Colin indicated, the .skp file seems to be unrecoverable.
Assuming you are using Windows, you could check in C:\Users\YourUsername\AppData\Local\SketchUp\SketchUp 2022\SketchUp\working\SKETCHUP and see if there’s a recovered backup file there.
It’s a shame that you threw away your backup file. Maybe in the future don’t be so quick to get rid of the .skb files.
You could check in the Recycle bin, in the hope you haven’t emptied that recently.
This might be worth a shot.
7 Ways to Recover Shift Deleted Files in Windows 11/10/8/7/XP.
As the OP iindicated, they use Shift+Delete so files don’t go to the Recycle Bin.
I realized that afterwards. Was being optimistic. Your article looks interesting.