vCenter Server Appliance 7.0
The update files stored in /storage/core/software-updates/ are corrupt.
To resolve this issue, the corrupted files within /storage/core/software-updates/ need to be removed. The /storage/core/software-update directory contains downloaded updates metadata and can be safely removed. The update metadata will be re-downloaded the next time updates are checked via the VAMI. For this reason, the next update check may be slower than normal.
If the issue persists after performing the above steps, follow the additional steps outlined in KB article 320702: