As Ernie correctly states, a 360 mini box doesn't have a hard drive and - by design - uses the HDD on the master box.
There's pictures of the master box here and the master/mini side-by-side here
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The OP stated they can’t play or delete recordings, which made me think one must be a main box.
Welcome to our Community Forums and thanks for posting.
The mini box will record on the hard drive in the main box.
If you have 2 mini boxes, then @Ernie_C is correct, you can not record since there is no hard drive.
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