Error: Could not reserve enough space for object heap

Learn how to resolve the 'Could not reserve enough space for object heap' error on your Minecraft server by adjusting RAM allocation and startup flags.

By AwakeNode Team Reviewed by harry Updated 15 June 2026

What this error means

The "Could not reserve enough space for object heap" error occurs when the Java Virtual Machine (JVM) fails to allocate the amount of RAM requested in the startup command. This usually happens because the host machine has insufficient physical memory available, or the operating system is restricting the process from accessing the requested heap size.

How to fix it

On AwakeNode

  1. Check your plan: If your server is hitting its memory limit, you may need to upgrade your hosting plan. On AwakeNode, upgrading your plan automatically updates your Xmx settings, so no manual configuration is required.
  2. Contact Support: If you believe your server has sufficient RAM but is still throwing this error, open a ticket with our support team. We can review your JVM startup flags and ensure they are correctly optimised for your specific environment.

On other hosts / manually

  1. Reduce Xmx: Locate your server's startup script or command line. Look for the -Xmx flag (e.g., -Xmx4G). Reduce this value to a lower amount that fits within your available system memory.
  2. Check 32-bit vs 64-bit Java: Ensure you are running a 64-bit version of Java. A 32-bit Java installation cannot address more than approximately 1.5GB to 2GB of RAM, which often triggers this error if you attempt to allocate more.
  3. Review other processes: Ensure that other applications running on the same machine are not consuming the memory required by your Minecraft server.

Frequently asked questions

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