How do you set the maximum java memory usage for Open Workbench versions

Document ID : KB000026995
Last Modified Date : 08/02/2019
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On a Windows workstation running OWB, the default maximum JAVA memory that is allocated for Open Workbench (OWB) is up to 500MB. You can modify the workstation's Windows registry to override the default memory allocation. This can help when running into issues saving large projects back to Clarity PPM.


    IMPORTANT: This article contains information about modifying the Microsoft® Windows Registry.
    Before you modify the registry, make sure to create a backup of the registry and ensure that you understand how to restore the registry if a problem may occur.
    For more information about how to back up, restore, and edit the registry, please review the relevant Microsoft Knowledge Base articles on

    Steps for setting maximum memory usage for Open Workbench:

    1. Start > Run, type in 'regedit' and click OK
    2. Drill down to

      on 32 bits Windows OS such as XP: HKEY_LOCAL_MACHINE\SOFTWARE\Niku\Niku Workbench folder
      on 64 bits Windows OS such as Win7: HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Niku\Niku Workbench
    3. Right click and select New > DWORD value
    4. Enter 'JavaMemoryLimit'
    5. Double-click 'JavaMemoryLimit'
    6. Select Base Decimal
    7. Enter a value in the Value Data field (Start with a value of 800, values higher then this can cause issues)
    8. Click OK and exit the registry


    • When adding the new value 'JavaMemoryLimit' it should be created as a DWORD and the unit is in megabytes. Thus a decimal value of 256 would allow allocation of up to 256MB.
    • When setting 'JavaMemoryLimit' the user would usually want to change the Base to be Decimal (not Hexadecimal) when setting the value.
    • If a user sets 'JavaMemoryLimit' to a value that cannot be honored then you may see Workbench start up (flash) and immediately shutdown.