Your Synology NAS encounters one of the following issues:

1. Unexpected shutdown or reboot (irrelevant to power supply issue)
2. Errors occurred when installing or updating DSM:
   1. ERR_PATCH_FILE (13)
   2. ERR_EXTRACT (26)

Run a memory test to ensure the memory (i.e., onboard memory and memory module) of your Synology NAS is working properly. We recommend running the test three times to make sure the memory is normal.

1. Download and install Synology Assistant (available at Download Center).
2. Launch Synology Assistant and click the upper-right icon.
3. Tick the Memory Test checkbox and click OK.
   
4. Select the Synology NAS to run the memory test. Make sure the status of the Synology NAS is Ready and then click the Memory Test button.
   
5. Follow the wizard to complete the process.

Your Synology NAS will be rebooted during the memory test. Do not close Synology Assistant during the test. During the test, the status of your Synology NAS will show Performing memory test (x%).

If your Synology NAS passes the memory test, the status of your Synology NAS will be Ready. At this time, you can run the test again if needed.

If your Synology NAS fails the memory test, the error message "One or more errors have been found by the memory diagnostic test" will appear on the screen. This indicates that the memory may be defective. In this case, we strongly recommended returning your Synology NAS for repair if it is still within the warranty period. Please note that even if your Synology NAS fails the memory test, its status will still show Ready.