I had to change the date of an event and I also had to restore my site from a backup. I am not sure which caused the problem, but I have emails showing me that several people registered for an event, but these folks don’t show up in the Registration list or downloaded file. Now I don’t even have their emails in order to ask them to register again. Where can I get the data that was lost?
This wouldn’t have done very much in terms of EE, certainly wouldn’t have lost data.
and I also had to restore my site from a backup.
So did you restore a database backup, files or both?
All of your event, registration, message etc data (in fact ALL of the EE data) is stored within the database, so if you restore a copy of the database from before the registrations were made you’ll lose those registrations.
Where can I get the data that was lost?
If you have restored a backup of the database that’s the only place the data is stored, so unless you have a backup of the database from BEFORE you restored your site (or your host has one) you can’t pull that data back as you’ve removed it from the database.