Debug.log errors help understanding

Any ideas how to troubleshoot below errors in log?

**2021-06-02T12:30:09.249 harvester chia.plotting.plot_tools: ERROR Failed to open file /mnt/plot_2/plot-k32-2021-05-28-18-04-

e963abff2746d8cf64dd996f3e4414cb23efb1a6810bc9007453da64642aab51.plot. Invalid plot header magic Traceback (most recent call last):
** File “/home/blahblah/chia-blockchain/chia/plotting/”, line 189, in process_file
** prover = DiskProver(str(filename))
** ValueError: Invalid plot header magic**

** 2021-06-02T12:37:33.997 harvester chia.harvester.harvester: WARNING Looking up qualities on /mnt/plot_2/plot-k32-2021-05-28-21-22-d69155ab85af1c33f4deb372293e7928370054cfbfdda9a63f2db17c98c7fb3c.plot took: 7.892041206359863. This should be below 5 seconds to minimize risk of losing rewards.**

I believe Chia is trying to check your disk that your plots are saved on, but your disks are most likely asleep and take longer than 5 seconds to respond to the read.

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Hmm strange, they are on ext USB3, so could be. The invalid plot header error is a strange one just for that particular plot ID. Thanks

The invalid plot header is likely a bad plot. There have been a few people reporting this problem. Usually the header region is zero’d out. In some cases it was tracked back to a bad file copy. In other cases plots that were previously good appear to have gone bad. I’ve not seen an explanation for how this happens. Some folks have started marking their plot volumes as read only (once filled). One quick check you can make is to look at the beginning of the plot with a file viewer on your platform, the beginning of the file should contain in ascii “Proof of Space Plot”. If this isn’t there the header region has been trashed somehow. If it is there something could still be wrong in the header causing the magic number check to fail.