Citavi reports that the project is read-only

Problem

After opening Citavi you receive a message that the project is read-only.

Causes and solutions

Missing license key

Enter your license key for Citavi for Windows.

Citavi 6

You are either not logged in to your Citavi account or there is no license key linked to your account.

Citavi 5 or earlier

You have not entered a license key in Citavi and have entered more than 100 references per project. Citavi Free has the complete functionality of Citavi for Windows, with one limitation: you cannot save if you have more than 100 references in all open projects. Please enter your license key.

Citavi project has "read-only" file property

In Windows Explorer, right-click the Citavi project file and then click Properties. Click General and then clear the Read-only checkbox.

Citavi project is "read-only" because it was opened directly from a ZIP file

Extract the project by right-clicking the ZIP file and clicking Extract all. Open the extracted project file.