IRPStackSize is too small

Sometimes jobs mail fail with one of the following Windows errors:

IRPStackSize is too small
Not enough server storage is available to process this command.

This error can be a bit confusing, as it is not related to disk space, rather it is caused when the IRPStackSize registry entry on the remote system is set too low.

IRPStackSize represents the amount of stack locations allocated for the Input/Output Request Packet (IRP) stack in Microsoft operating systems. The value of your IRPStackSize influences the amount of allocated bits of memory your operating system can use to transport files or do any other sort of I/O operations within the system.

The solution is to increase the IRPStackSize in the remote system’s registry. Please be extremely careful when editing your registry, and when possibly make a backup before making any changes. For more information, please refer to the relevant Microsoft Knowledge Base articles on

By default, the Windows IRPStackSize is 15, and the maximum value is 50. Microsoft also notes that values between 33 and 38 are not recommended.

Locate and then click the following registry subkey:

If the IRPStackSize entry is not present in this subkey, follow these steps:

  1. Click Edit, point to New, and then click DWORD Value.
  2. Type IRPStackSize, and then press ENTER.
  3. Note Type IRPStackSize exactly as it appears. The value is case sensitive.

Click IRPStackSize, click Edit, and then click Modify.

In the Data Value box, type a larger value, and then click OK.

For more information refer to following Microsoft KB article:

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