Configuring Support for Long Path Names in Altium Designer

Starting from Windows 10 version 1607, MAX_PATH limitations have been removed from common Win32 file and directory functions. However, you must opt-in to the new behavior by changing a registry key to enable support for actions when a file path with the file name exceeds 256 characters, such as:

  • Opening a project from the connected Workspace.
  • Making a local project available in the Workspace.
  • Changing the folder path in an Outjob file.
  • Generating outputs using an Outjob file or the Project Releaser.
  • Saving a project as a project template to the Workspace.

WARNING: Modifying the registry improperly can result in Windows becoming unusable. Use the Registry Editor only at your own risk and only after backing up the registry as outlined in the Microsoft article How to back up and restore the registry in Windows.

  • The long path support is in Open Beta and available when the System.LongPathsSupport option is enabled in the Advanced Settings dialog. The option is available in the dialog only after applying a change to the registry as described below.

  • When releasing a project that uses a long path to an Enterprise Server Workspace, the PC where the Altium On-Prem Enterprise Server is installed should also be configured: learn more.

  1. Click Search (shortcut: Win+S), type regedit.exe and then press Enter.

  2. In the Registry Editor, navigate to the following location: Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem.
  3. Right-click the entry named LongPathsEnabled and select Modify.
  4. Set the Value data to 1 and click OK.

    If the registry key does not exist, the entry can be added by doing the following:

    1. With the FileSystem folder selected, right-click in the empty space of the Name column where the registry keys are located, and select New » DWORD (32-bit) Value from the context menu.
    2. Name the key LongPathsEnabled and press Enter.
    3. Right-click the entry named LongPathsEnabled and select Modify.
    4. Set the Value data to 1 and click OK.

    This registry key can also be controlled via Group Policy at Computer Configuration > Administrative Templates > System > Filesystem > Enable Win32 long paths.

    Learn more about how to Enable Long Paths in Windows 10, Version 1607, and Later.

  5. Restart the PC.
  6. In Altium Designer, enable the System.LongPathsSupport option in the Advanced Settings dialog and restart Altium Designer.
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Note

The features available depend on your Altium product access level. Compare features included in the various levels of Altium Designer Software Subscription and functionality delivered through applications provided by the Altium 365 platform.

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