While working with SharePoint 2013 restore and backup I got interesting error in one of my host named site collection (I hope this is generic issue, not specific to host named site collection) saying as shown the image below.
When I try to fix this issue from SharePoint central administration quotas, all the options are disabled and unable to change anything as shown the image below.
By going through some of the blogs, I got the issue. In SharePoint 2013, we are having Manintanence Mode property for SPSite makes SharePoint site is undergoing a Maintenance & is read only. We can set this SharePoint site when content DB is in read only state, or when SharePoint site upgrade, moving SharePoint site in process.
We can fix this error by clearing ClearMaintenanceMode method in SpSiteAdministration object. We can do this by running following command,
$Site = new-object Microsoft.SharePoint.Administration.SPSiteAdministration(SITE URL) $Site.ClearMaintenanceMode()
This fixed my issue. Hope this helps.