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Reading the OneSigner Log Files: Where They Are and What Matters

Nov 2, 2026 · 2 views

This guide explains where to locate OneSigner log files, how to interpret daily signing history records, how to check the Windows Event Log for service-level events, and how to enable verbose command-line diagnostics when troubleshooting integration or token access issues.

Prerequisites

To inspect OneSigner logs on your Windows machine, ensure you have the following:

  • Administrator access to the Windows server running OneSigner (Windows 10/11 or Server 2019+).
  • Local read access to the installation directory at C:\OneSigner\app.
  • Access to the Windows Event Viewer on the host machine.

1. Locating the Daily Signing History Logs

OneSigner writes an operational record of every completed signing transaction to a flat file on disk. These files record PDF signatures, code-signing operations, and status requests processed by the engine.

  1. Open File Explorer on your signing host and navigate to the default installation directory: C:\OneSigner\app\logs\
  2. Look for files named in the format signing-YYYY-MM-DD.log (for example, signing-2026-03-30.log). A new file is created automatically for each calendar day when signing activity occurs.
  3. Open the log file using any plain text editor, such as Notepad or Notepad++.

Each entry in the daily signing log is tab-separated. The file records the exact timestamp, the signing profile or tenant invoked, the target file name or hash, the certificate thumbprint used, and the final status (such as success or failure). You can also view these records directly inside the eSign portal under Management → Logs if your account role permits access.

If you experience issues where jobs fail before reaching the signing engine, check your hardware token connection and ensure an interactive Windows session is available.

2. Inspecting the Windows Application Event Log

While daily transaction logs track file-level signing success and failure, the Windows service itself logs lifecycle events, startup errors, and crash reports directly to the operating system.

  1. Press the Windows Key, type Event Viewer, and press Enter.
  2. In the left-hand navigation pane, expand Windows Logs and click on Application.
  3. In the right-hand Actions pane, click Filter Current Log....
  4. Under the Event sources drop-down menu, select OneSignerService (or search for entries originating from the service). Click OK.

Success looks like clean startup and operational entries. Error entries will capture service-level events or failures to communicate with attached USB tokens via PKCS#11 or CSP/KSP drivers.

3. Enabling Verbose CLI Diagnostics

When investigating command-line tool calls, REST API integration errors, or OneSignTool / AzureSignTool proxy traffic, the standard logs may not show enough detail about the HTTP request payload or cryptographic handshake.

  1. Open the Windows System Properties or environment variables configuration on your signing host.
  2. Add a new system or user environment variable named ONESIGNER_CLI_LOG and set its value to info.
  3. Restart the service from an elevated command prompt to apply the new environment variable:

    net stop OneSignerService
net start OneSignerService
  4. Execute your signing command or API request again. Diagnostic output will now print detailed execution steps, allowing you to isolate whether a failure stems from an incorrect token PIN, an expired profile, or malformed API parameters.

When your diagnostic session is complete, remove or clear the ONESIGNER_CLI_LOG environment variable to prevent excessive disk writes on your production machine.