hashicorp/packer · error

Error uploading script

Error message

Error uploading script: %s

What it means

The PowerShell provisioner uploads the generated script to the remote machine via the communicator inside a retry loop (retry.Config with StartRetryTimeout). This error wraps any failure returned by comm.Upload, such as SFTP/SCP protocol errors or connection drops. The retry loop will keep re-attempting the upload (seeking the file back to offset 0 each time) until StartRetryTimeout expires, then surface this wrapped message. It means the script file never reached the guest, so the provisioner cannot execute it.

Solutions

1. Check guest connectivity and that the SSH/WinRM service stayed up during the build; fix any reboot or network instability.
2. Verify the remote_path directory exists and is writable by the connecting user on the guest.
3. Check free disk space on the guest where remote_path lands.
4. Increase start_retry_timeout so transient outages are retried longer.
5. If uploads consistently fail, test the communicator (e.g. ssh -vv / WinRM logs) to identify protocol-level problems.

Example fix

// before
"start_retry_timeout": "5m"
// after (allow longer retries for flaky guests)
"start_retry_timeout": "15m"

// before building: verify guest reachability and writable remote path
ssh user@host "test -w $(dirname /path/to/remote) && df -h $(dirname /path/to/remote)"

When it happens

Trigger: comm.Upload returns a non-nil error while provisioning: SSH/SFTP connection reset mid-upload, guest disk full, permission denied writing to RemotePath, or the remote host rebooted during the upload retry window.

Common situations: WinRM/SSH guest briefly restarting during provisioning; remote path on a full or read-only volume; firewall dropping long-lived SFTP sessions; using a communicator whose upload implementation rejects the file size or path; temporary network flakiness in CI.

Related errors

• clean up script failed to upload
• Error uploading ps script containing env vars
• Bad script
• is an invalid Trace level for `debug_mode`; valid values…
• Either a script file or inline script must be specified.

AI-assisted analysis of hashicorp/packer@eb36e3c3e4 (2026-09-05). Data as JSON: /api/errors/39fd9e0f937ba523. Report an issue: GitHub.

Appendix: source

Thrown at provisioner/powershell/provisioner.go:394

		}
		defer f.Close()

		command, err := p.createCommandText()
		if err != nil {
			return fmt.Errorf("Error processing command: %s", err)
		}

		// Upload the file and run the command. Do this in the context of a
		// single retryable function so that we don't end up with the case
		// that the upload succeeded, a restart is initiated, and then the
		// command is executed but the file doesn't exist any longer.
		var cmd *packersdk.RemoteCmd
		err = retry.Config{StartTimeout: p.config.StartRetryTimeout}.Run(ctx, func(ctx context.Context) error {
			if _, err := f.Seek(0, 0); err != nil {
				return err
			}
			if err := comm.Upload(p.config.RemotePath, f, &fi); err != nil {
				return fmt.Errorf("Error uploading script: %s", err)
			}

			cmd = &packersdk.RemoteCmd{Command: command}
			return cmd.RunWithUi(ctx, comm, ui)
		})
		if err != nil {
			return err
		}

		// Close the original file since we copied it
		f.Close()

		// Record every other uploaded script file so we can clean it up later
		uploadedScripts = append(uploadedScripts, p.config.RemotePath)

		log.Printf("%s returned with exit code %d", p.config.RemotePath, cmd.ExitStatus())
		if err := p.config.ValidExitCode(cmd.ExitStatus()); err != nil {
			return err

View on GitHub (pinned to eb36e3c3e4)