Chapters missing

I can not find all the work I have been doing since I saved a copy on the 30.3, more than 100 pages, can they have been lost, or are they in a different version. Please help

Need more information.

Scrivener does not ‘lose’ work.

Are you using a cloud service?

If so:
Are you saving projects in a local folder as opposed to direct to the cloud?
Do you have ‘save offline’ or the equivalent selected. Called by different names depending upon cloud service. Might be ‘optimise storage’, ‘make available offline’…

Do you have auto backups selected (How many - 25 is better than the standard 5)?

Don’t go poking around in the backups before you provide above answers.