ERROR EC1058: Unable to read backing store file [path]: The system cannot find the file specified
EC1058 means that the eMake backing store file changed from underneath it. This means that a file that eMake believed should have been in its temporary directory was either moved, renamed, or its permissions modified during the build such that it became inaccessible.
This can happen if you have another process running in the background on the same system. From previous cases, common culprits are antivirus, build clean up scripts, and so on.
Suggestions for resolution:
If you are aware of other processes that may be attempting to move or modify files in the eMake backing store, turn them off (or configure them to avoid changing tmpdir files during a build).
If not, and the problem persists, keep a Process Monitor trace running on the eMake machine at the same time as the build - it will show us definitively what is happening to the files in the backing store. You can get Process Monitor from https://docs.microsoft.com/en-us/sysinternals/downloads/procmon.