In an Indesign CS5 document converted to CS6, locked anchored objects cannot be unlocked (even with "Prevent Selection of Locked Objects" unchecked). "Unlock All on spresd" has no effect. Indesign 8.0.1Windows
I don't think I've seen this, but I don't do a lot with anchored objects, and I'm not certain what you mean by locked in this case. Did you already overwrite the CS5 version? If not, export it from CS5 to .idml and open that in CS6. If you have, try exporting from CS6 and see if it helps.
If neither helps, I think we'll need more details about the file, and perhaps an actual sample file to look at.
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