Document LFS integrity check and how to disable it

doc/workflow/lfs/manage_large_binaries_with_git_lfs.md

@@ -163,3 +163,11 @@ For Windows, you can use `wincred` or Microsoft's [Git Credential Manager for Wi
 
 More details about various methods of storing the user credentials can be found
 on [Git Credential Storage documentation](https://git-scm.com/book/en/v2/Git-Tools-Credential-Storage).
+
+### LFS objects are missing on push
+
+GitLab checks files to detect LFS pointers on push. If LFS pointers are detected, GitLab tries to verify that those files already exist in LFS on GitLab.
+
+Verify that LFS in installed locally and consider a manual push with `git lfs push --all`.
+
+If you are storing LFS files outside of GitLab you can disable LFS on the project by settting `lfs_enabled: false` with the [projets api](../../api/projects.md#edit-project).