Speed-up your virtual machine created with VMware Player

If your virtual machine created with VMware Player becames very slow and takes a long time to complete some operations it’s time to improve its performance!
Close your VM, and open the *.vmx file with a text editor. Then add at the end of the file the following lines:

mainMem.useNamedFile = "FALSE"
sched.mem.pshare.enable = "FALSE"
MemAllowAutoScaleDown = "FALSE"
prefvmx.useRecommendedLockedMemSize = "TRUE"
prefvmx.minVmMemPct = "100"

Remember to not duplicate the keywords (in case you already have some lines set) otherwise the VM will not start.
The above lines totally reserve the memory requested by the VM to the guest system and avoid to continuosly ask to the host (and so to the swap file) for new memory chunks.

Try yourself and give me a feedback!


  1. Are you sure it is a text file ? Cannot read it with notepad.

    • Hi Gerard,
      yes it is a text file… make sure to open the *.vmx file and not the *.vmdk one.

  2. Hi Matteo,
    Many thanks for share this information. It works for me! I am using MAC Leopard as guest and your modification in the .vmx file made miracles!

    • Just came across this post whilst searching and I want to say thank you! This has really made by VM’s much faster. It is a great tip, so thank you very much. :)

  3. grazie per la dritta!

  4. Thank you for the VM speed tip Matteo.
    Allow me to add a tip i saw on some site with similar solution :
    When you finish editing the .vmx file in windows 7, Choose to save the file in UTF-8 format, because windows 7 tries to automatically save it as ASCII file

  5. MCE

    I get an error when trying to use this on VMWare Player 6, it says corrupted file (I’ tried even saving it as a UTF-8 and also ensured it isn’t repeated)

    • Can you try to add one line at the time and test which one corrupts the file?
      I don’t use VMPlayer 6 but, if the configuration format file is the same, they probably changed the configuration keywords.
      Let me know.

      • Ciao matteo, scusa ma dove trovo il file vmx?sotto quale cartella?Grazie ciao.

        • Lo trovi nella stessa cartella in cui sta l’immagine disco della macchina virtuale (*.vmdk)

  6. GRAZIE MILLE! mi hai risolto un gran problema

  7. Zefoln

    MANY THANKS!! I’m surpised that 2 years later this still works for VMPlayer. I had bouts of high disk usage with Vmplayer 6 (latest) and Windows 8.1. Matteo…you have helped restore my development environment. I am grateful for this.

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