Error unexpected file format 2023

Please help me to recover this file … Was working on a file last night. Tried to open it this morning and got the unexpected file format message and even a bug splat when trying to open it. you can see the model in preview thumbnails but you can’t open it I am working in 2023 version.

I heard about your file from a colleague, and sent them a recovered version of the file. You may have received the link from them by now, but just in case, here it is:

Thank you for your quick response about the invalid file format issue. I was wondering if you could let me know how you fixed it so that I can use the same method if I face similar challenges in the future. Thank you!

I don’t know if any of this is specifically related to the issue you were having with your model but it wouldn’t hurt to clean it up before you go forward with it.

First, there are a lot of reversed faces in the model. I temporarily changed the back face color to magenta to make them more evident.

Ensuring correct tag usage will go a long way toward making your model easier to work with. All edges and fces should be created and remain untagged.
Screenshot - 7_11_2023 , 2_41_38 PM
And purging unused stuff regularly will help.
Screenshot - 7_11_2023 , 2_42_08 PM
In this case the purge reduced the file size by 51%.

There seems to be some action people are doing that can leave some of the data in the model being incorrect. We still don’t know what the action is that is causing the problem, but we have tools that can skip those incorrect items instead of failing to open the whole file. In your file’s case there is a group named Group#874 that has something wrong with it. The model I sent back to you has that group removed. Hopefully it wasn’t an important group!

The backup file you provided already had the problem in it. I’m trying to get a model that won’t open, but its backup does, to then hopefully be able to repeat the actions that were done that introduced the problem.