You launch an elevated instance of SharePoint Designer 2013 (i.e., as Administrator), and then connect to a web. In the Navigation panel, you open the Lists node, and then select a particular list so as to edit one of the forms associated with this list. You select the list, and then click the Check Out button on the ALL FILES ribbon. You then click on the file name itself so as to edit it, but then experience the following error:
- Undo the checkout, then click on the file name: still get error.
- Exit Designer, launch it again, and then try: still get error.
- Relaunch Designer as Administrator, but then open the web using the SharePoint Setup User Administrator account, and then try again: still get error.
- Logout out of your workstation (you're logged in using your standard account), log back in using your administrator account, and then try again: still get error.
- Perform literature search and find several articles suggesting permissions and Designer configuration issues might be the cause.
- Checked administrator account privileges: found that it wasn't configured as a site collection administrator for the site collection containing the web. So, configured the administrator account in Central Administration as secondary site collection administrator, and then tried again: still get error.
- Checked Designer configuration for web: all items enabled.
- Reviewed literature again, noting that some authors found that uninstalling and re-installing Designer solved this problem.
- While logged into workstation as administrator, uninstalled and re-installed SharePoint Designer 2013, and then tried again: error no longer appeared.
- Given all appropriate permissions and Designer settings configured, re-install SharePoint Designer 2013.