High CPU Issues on Zyxel NAS

This article describes how to fix a high CPU (~100% CPU) issue on a Zyxel NAS.

A high CPU can slow down or even damage your NAS. This tutorial will show some possible sources of high CPU occurring!

Walkthrough Steps

If you are experiencing that your NAS is constantly running at a CPU level of 90% or even higher.
Please follow these steps to deactivate two functions that might be responsible for this:

1. Log in to the unit by entering its IP address and the credentials for an admin account (by default the username is “admin” and the password is “1234”)
2. Click on the myZyxel cloud icon located in the upper left corner of the screen and click on the switch of “Generating thumbnail for multimedia files, which is within share folders” to set it to “Disable”
3. Close the myZyxel cloud window and click on the “Control Panel” app on your app's overview
4. Navigate to Service > Media Server, untick the checkbox “Enable Twonky Server” and click apply

Please note: You need to consider if you really want to deactivate these services. If you are fine with not using thumbnails in the gallery app and might want to use a streaming stick as an alternative to the Twonky server, then you are free to disable these.

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