CMOS checksum error - Defaults loaded

Not open for further replies.


New member
Jun 6, 2021
Every time we turn this computer on from being off, we get the error
“CMOS checksum error - Defaults loaded”
“Press F1 to continue, DEL to enter setup”
This PC wasn’t used for several months as it is in the managers office of a small cafe.
Is it an easy fix or will we need to replace it or get a technician? We are reluctant to contact the people that provided it as it forms part of our EPOS system and they charge a lot of money to come out which we can ill afford at the moment
Hello and welcome.

This sounds like the CMOS battery has died. It’s a pretty simple job to swap if this is a standard desktop PC .

Just open the cover and look for the coin cell battery on the main motherboard, and change it. Normally it is a CR2032.

You will get the error once more when you start the system and you may need to reset the clock, but after that it should be good.
Last edited:
Thanks very much!!!
I was quite apprehensive about this as although I have a bit of software experience i’m no computer expert.
The hard bit was finding the replacement battery as you mention it was a case of taking the cover off and looking for the battery. Real easy to get out and pop a new one in.
You’ve saved a small business some money after what has been a real hard period so I cannot thank you enough!
Not open for further replies.