This post over at the DayZ forum makes sense.
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I used to have the same problem when I logged out.
I worked out it was because I didn't wait for the Hive update communication (as Detta mentioned).
Since the "not saved" time thingy was removed from the Debug Monitor I had forgot all about it.
So now you need to do this:
Press "P" and click on your name, look at the numbers on right "Ping" and Bandwidth".
When they change you are good to go.
I always wait for them to change at least twice just in case.
Never had a problem since.
Hope this helps.
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http://dayzmod.com/forum/index.php?/topic/53313-best-way-to-safely-log-out/#entry515506

Thats interesting I'll keep that in mind from now on!

I think we have all been through that. Logging out after playing for awhile only to find our character back at the coast when we log back in. It is good to have the survival gear and guns, but still its a PITA to get back to where you were.