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CrashPlan Support

Adjusting CrashPlan Settings For Memory Usage With Large Backups

Applies to:
  • CrashPlan for Home
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This article is intended for CrashPlan for Home users. For Code42 CrashPlan and CrashPlan PRO documentation, read this page on our enterprise support site.


The amount of available memory needed to use the CrashPlan app increases with the size of your archive or backup file selection. If your backup selection exceeds 1 TB of storage or 1 million files, you can increase the maximum amount of memory the CrashPlan app is allowed to use by following the steps below.

Alternatively, if your computer has memory limitations, you can adjust several CrashPlan settings to reduce the amount of memory required for your backup.


CrashPlan backup selections exceeding 1 TB of storage or 1 million files.


  • CrashPlan uses memory up to the maximum allotted. The maximum is used only if it is needed.
  • Code42 typically recommends allocating 1 GB (1024 MB) of memory per 1 TB of storage (or per 1 million files). Although CrashPlan only requires approximately 600 MB of memory per 1 TB of storage (or per 1 million files), our recommendation is intended to account for growth in your file selection.
  • If you uninstall and reinstall the CrashPlan app after increasing allocated memory, the setting will revert back to the default value of 1024 MB.

Sample recommendations

Backup Selection Size Recommended Memory Allocation (MB)
Up to 1 TB or up to 1 million files 1024 (default)
1.5 TB or 1.5 million files 1536
2 TB or 2 million files 2048
2.5 TB or 2.5 million files 2560
3 TB or 3 million files 3072

Memory limitations

You should not allocate more memory to CrashPlan than the maximum supported by your computer. For example, if your computer has 8 GB of RAM, you shouldn’t allocate more than 8 GB (8192 MB) to CrashPlan.

Windows XP And Windows 32-bit Operating Systems
If you are running the CrashPlan app on Windows XP or Windows 32-bit operating systems, we recommend limiting the amount of memory allocated to the CrashPlan app:
  • Windows XP: If you experience issues when trying to open or use the CrashPlan app, reduce memory allocation to 768 MB or 512 MB.
  • Windows 32-bit: On computers running a 32-bit Windows operating system, programs are limited to a maximum of 2 GB of RAM. After accounting for other resources required by your system, this limits CrashPlan's maximum memory allocation to approximately 1200-1500 MB. If you are running a 32-bit operating system, we recommend allocating a maximum of 1536 MB of memory to CrashPlan. Alternatively, you can remove files from your backup selection to reduce the size of your backup archive.

Recommended solution

You must have version 3.6.3 or later of the CrashPlan app to use this solution.

You can use the CrashPlan app's manual commands to increase the default memory from 1024 MB to a maximum that supports your archive size.

  1. Open the CrashPlan app
  2. Double-click the CrashPlan logo in the upper-right corner
  3. Enter the following command, using a value appropriate for the size of your backup selection (for example, 1536 for a 1.5 TB selection):
    java mx 1536, restart
    The CrashPlan app closes
    Deauthorize app
  4. Open the CrashPlan app and sign in

Alternative solution

CrashPlan only uses the maximum memory alloted if it is needed. However, if the maximum memory supported by your computer does not accommodate the size of your backup file selection, there are several alternative ways to reduce memory usage.

Remove system and application files from your backup selection

CrashPlan is designed to back up personal files (e.g., photos, documents, music, etc.). It is not designed to back up your operating system or application files. When system and application files are included in your backup file selection, CrashPlan expends additional resources, like memory, backing up these files. It's truly wasted effort because CrashPlan isn't designed to help you recover your operating system or applications. Review our guidelines for choosing what to back up for additional information.

Reduce backup frequency

CrashPlan monitors changes to files in real time based on your backup frequency and versions settings. More frequent backups or large numbers of files require the CrashPlan app to use more system resources to process your backup. You can reduce the frequency of the New Versions scan to conserve memory.

Real-Time File Watching
Real time file watching can be disabled from the CrashPlan app under Settings > Backup > Advanced settings to further reduce memory usage. However, by turning this setting off, your files only back up after running a verification scan. Real-time file watching is recommended for ensuring your most recent changes are backed up in a timely manner.

Reduce CPU allocated to CrashPlan

You can control the CPU CrashPlan is allowed to use both when you are present (working on your computer) and away. You can adjust these settings from the CrashPlan app under Settings > General. While most modern computers can support allowing CrashPlan to use a high CPU percentage without experiencing any performance issues, you may want to adjust these settings for older computers.

Schedule backup

Finally, if you are still experiencing performance issues related to memory, you can configure CrashPlan to back up only at specified times. You can adjust your backup schedule from the CrashPlan app under Settings > Backup > Backup will run. However, be careful to set a schedule that allows CrashPlan to run while your computer is on and not in standby mode.

Reduce your file selection

If you experience issues related to CrashPlan's memory usage after adjusting the settings described above, you may need to remove files from your selection to reduce the amount of memory needed to run the CrashPlan app.

Removing Files
Removing files from your backup file selection permanently removes them from your backup archive. You cannot restore files that have been removed from your backup file selection.