It may be a good idea to back up your library regularly, even if you have synchronization in use. Note! This is not a must and nothing you need to do as a beginner.
You can back up your library by going to “Edit” -> “Preferences” in the Zotero program. Select the “Advanced” tab, then the “Files and Directories” subtab. In the second field is a button that says “Show Data Catalog”.
Click on it and a folder will open on your computer where all the Zotero data is located, probably with the address C:\Users\username\Zotero. Then close Zotero, if you tinker with the data while the program is open there is a risk of corruption. Copy all files and folders contained in the folder.
Create a folder where you want to back up the files: a usb stick, ÅA's home area, OneDrive, etc. Paste the files and folders, and you've made a backup! Feel free to include today's date in the name of your backup folder so you know when you made the last backup. Try to remember to do this regularly, such as the first or last day of every month.
Restore your library
If you have problems with your library, you may need to restore it, and you do this using your backup in the following way:
Go to the data directory as instructed above. Create a temporary, new folder on your desktop. Select the zotero.sqlite and storage files from the data directory and move them to the temporary folder.
Open your backup folder and select the same files from there and copy them over to the data directory. The Zotero library should now work, and you can delete the temporary folder.
More information about and options for restoration on the Zotero site .
In case of problems, it’s good to first search for a solution in the Zotero Forums or Zotero's support . The Zotero Forum is very active and users often offer each other customized solutions, so it's likely that you'll find someone who has run into the same problem as you at some point.
If you can't find the solution in the Zotero Forums, you can contact the library .