(un)Mavericks will not see most of my USB keys

Has anybody had problems with usb keys and Mavericks.

I have a bunch of keys that I use within my mac ecosystem. They work on all macs (osx10.6 or higher) except on Mavericks.

On mavericks they show up on the sidebar (but with no data in them) and not on the desktop (although the setting is for this to happen).

But when I try the key on previous OSX, they work fine.

Any input welcome.

ivnj said:

I just checked and my dane elec 16gb works fine. Sometimes in preferences you forget to checkmark show external hard disks also.

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the settings are correct, that was the first place I checked

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Fimeg said:

I had the same problem, but all I did was reboot and reset PRAM.

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xgman said:

Just copy any data off in another machine, reformat them in Mavericks and then copy the data back on. Sometimes that will clear everything up.

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Between the 2 I think i'll try the reboot, don't see why Mavericks would need to be the sole "Formatter" of USB sticks...

Thanks for input