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What does Read-Only Mode mean?
Read-Only mode is a technical term defining a period of time where information can only be viewed and cannot interact with. When deviantART enters Read-Only mode you will only be able to view the site and will not be able to interact with the site as you normally would while logged in. If you were logged in prior to going into Read-Only mode you will see the site as if you were logged out and once the site returns to normal your login cookies will be checked allowing you to resume being logged in. The causes of Read-Only mode include when the site is undergoing major maintance usually for certain upgrades and modifications or when one or more of the servers isn't synchronized with the rest of the set thus allowing the de-scynchrnized server to catch up.
Please keep in mind that there isn't a set time frame as to how long Read-Only mode may last so we simply advise that you take a break and come back to the site at a later time. We also advise that if you were logged into a public computer when the site changed to Read-Only that you clear your cookies so when the site returns to normal you will no longer be logged in.