Set a Site Collection to Read Only via PowerShell

If you need to set a site collection to read only, all you have to do is run two lines in PowerShell.

First, to verify the results, let’s look at the site when it is NOT read only:

As you can tell by the ribbon UI, you are able to select New Document, Upload Document, and New Folder. Now, let’s run the following from the SharePoint 2010 Management Shell:

$site = Get-SPSite -Identity <site url>
$site.readonly = $true

Refresh the page and notice how the previously available options are now grayed out:

Also notice that even the Add document link under the document has been removed, since you are no longer able to add documents in its read only state.

When you are ready to switch back, simply run the lines again with $false:

$site = Get-SPSite -Identity <site url>
$site.readonly = $false