Intellij Annotate Option Grayed Out

If you check File > Settings > Version Control and see that your current project is listed under "Unregistered Roots", go to (on the menubar) VCS > Enable Version Control Integration. It will ask you to select the VCS tool you use, then click ok and you'll have all the integrations working (including the annotate feature which uses git blame).

The answer by @activedecay let me in the right direction. In my case, I have a multi-module project - each has a separate git repo - but we're all in the same workspace.

In my case, Intellij IDEA 2017.2, the Preferences -> Version Control panel shows a listing of all the project roots. The module with the disabled "Annotate" option was in the "Unregistered Roots" section.

To fix the problem, I selected the module and pressed the "+" icon in the lower toolbar to register the module root with Intellij VCS. The change is immediate and the "Annotate" options becomes available.

Looks like its a fresh project. First configure the Version Control like Git and than commit at least once. After first commit Annotate option will not be grayed out.

Also update git for any new version.