Summary

A Refnum error typically indicates that one or more GibbsCAM user preference files have become corrupted.

In most cases, the issue is resolved by deleting the User Preferences folder, allowing GibbsCAM to recreate a fresh set of default preference files the next time it launches.

Table of Contents

Before You Begin

Before performing the troubleshooting steps:

  • Close all instances of GibbsCAM.

  • Ensure you know which version of GibbsCAM you are using.

  • Be aware that deleting the User Preferences folder resets your personal interface and preference settings to their defaults.

Note: This process does not delete your part files, tooling libraries, or machine definitions. Only user-specific settings are reset.

Procedure

Step 1 – Close GibbsCAM

Close all running instances of GibbsCAM.

If necessary, verify in Windows Task Manager that no GibbsCAM processes remain running.


Step 2 – Locate the User Preferences Folder

Open File Explorer and browse to:

C:\Users\<username>\AppData\Roaming\Gibbs\GibbsCAM\<version>


Replace:

  • <username> with your Windows user name.

  • <version> with your installed GibbsCAM version.


Step 3 – Remove the User Preferences Folder

Rename or delete the entire folder.

Recommended: Rename the folder first (for example, append _OLD) so it can be restored if necessary.


Step 4 – Launch GibbsCAM

Start GibbsCAM normally.

When the software launches, it automatically creates a new User Preferences folder using the default settings.

Expected Result

GibbsCAM launches successfully with a newly created User Preferences folder and the Refnum error is resolved.

Additional Information

What Causes a Refnum Error?

A Refnum error is most commonly caused by corruption within the GibbsCAM User Preferences folder.

Preference files can become damaged due to:

  • Unexpected system shutdowns.

  • Software crashes.

  • Interrupted writes to configuration files.

  • Corruption within the Windows user profile.

Deleting the User Preferences folder forces GibbsCAM to rebuild a clean set of configuration files.

Common Causes

This error is commonly associated with:

  • Corrupted preference files.

  • Damaged user profile data.

  • Interrupted GibbsCAM shutdown.

  • Configuration file corruption.

Best Practices

  • Always close GibbsCAM normally before shutting down Windows.

  • Regularly back up custom preferences if they are heavily customized.

  • If startup problems begin after a crash, reset the User Preferences folder before attempting a complete reinstall.

Troubleshooting

  • Problem: The Refnum error still appears after deleting the User Preferences folder.

Possible Causes

  • The preferences folder was not recreated successfully.

  • The GibbsCAM installation has become corrupted.

  • Another configuration file is damaged.

Resolution

Run the GibbsCAM Recovery Tool. If the issue persists, perform a complete reinstall of GibbsCAM, making sure not to migrate the previous User Preferences folder.


  • Problem: The User Preferences folder cannot be deleted.

Possible Cause

GibbsCAM is still running in the background.

Resolution

Close all GibbsCAM processes using Windows Task Manager, then try deleting or renaming the folder again.

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Keywords

Refnum, Refnum Error, Corrupted Preferences, User Preferences, AppData, Startup Error, Configuration Files, Recovery Tool, GibbsCAM Crash