You may face to this problem when you are running SharePoint 2013 with limited Hardware Resources. When Processor and Memory utilization is higher you may get this frequently. This can be even worse if you are running SharePoint in a VM with less resources.
In my test environment I had 8 GB Ram for SharePoint Server 2013 ENT which is not really recommended but I had no option due to my hardware box was fully utilized so couldn’t allocate much resources to this VM.
To solve this out temporary we can search a different user instead of keep trying to add the same one. Wait a 30 second and try to add "Everyone" –> Error again –> then try another –> now try your originally needed one –> success !
Though it’s a development environment you have to at least allocate 12 GB of memory with Minimum 2-4 Cores v processor if it’s SharePoint 2013 which is depends on how many web applications/Site collection being created and used frequently for your day to day developments.
Refer here for Microsoft recommendations on hardware perspective – http://technet.microsoft.com/en-us/library/cc262485.aspx#reqOtherCap