When using the "hco" command line utility, some files are not being downloaded in a Checkout to a shared path.
same error for those files:
E03020028: The File Agent error for item <servername>\\<drive>\<path>\<filename>: Can't open signature file.
Harvest Software Change Manager all versions
Add the "-nvs" option to their hco command.
More information about the "hco" command line utility can be found here: Command Reference - hco Command-Check-out
Sometimes intermittent network interruptions can cause Harvest to temporarily not be able to read/write to the mapped network drive. In such cases, a proposed workaround is to install the SCM agent on the target machine and check out using the agent instead of a mapped network drive.