Airport time capsule 5th gen 2TB

First thing to figure out is if the message is real or due to failure of sensor which is common.

How hot is the top of the unit? It should just be warm to touch?

Is the fan running? Put your ear onto the top of the unit and see if you can hear the fan running.. it should be very quiet.. but you will hear it up close.. don't confuse with hard disk spinning if it is running.. you can tell because the hard disk vibration is much greater than fan.

You can also dig this info out of the airport utility.. fan speed is listed.

Click on edit and go to the top menu.. More recent versions of Airport Utility may use a different name but it is the same thing.

If it is off,, i.e. you are not selling your secrets to Apple.. turn on Diagnostics and wait a few minutes for it to do the readings.

Under thermal info you will see RPM of the fan. You will also see bad sensor or bad fan listing.. in my case the fan is doing 5000rpm and is roaring.. it should do 1500rpm and near silent.

There is also temp info but in hieroglyphics .. number are meaningless to me.

Anyhow.. you are now able to decide if the issue is meaningful or not.

An overheat message can be false.. so if the TC is not hot to touch nor the fan doing 5000rpm so you can hear it from the next room.. then a possible fix is simple.

In the airport utility click edit.. go to the Internet tab.

Add a DNS to the list.

I use 8.8.8.8 or 1.1.1.1

Ignore all the other details which will be different on your TC to mine.. the only thing that are doing is adding the second DNS value.

Then update.. The overheating warning will go away.

If you power down the TC and start up again it will likely return.. so this time remove the added DNS.. all you are doing is making a small change which causes a warm restart of firmware.. not a full cold restart.

Tell me if it works.

The other issue can be fan clogged with dust or actually failing.. in which case the TC will be hot to touch and you will need to figure out if changing or at least cleaning the fan is worthwhile.. it is not easy to do.. and many people break things if they attempt it themselves.

If the TC is 5+ years old it is due replacement so forget about it. Less than 3 years might be under AppleCare if you have any current. Ring Apple as rules are complicated.

For 3-5 years.. and you are a DIYer the instructions for strip down are in ifixit

https://www.ifixit.com/Guide/Airport+Time+Capsule+A1470+Hard+Drive+Replacement/61924

Edit.. as per suggestion from taylormark1234

Blowing out the dust.. can work.. if the dust is clogging the bottom vents but I doubt it will clean the fan which is right at the top of the unit..

Good luck with it though.

This is a common problem on AirPort Extremes and Time Capsules. The problem is that there is too much dust blocking airflow in the unit. I had this exact problem and I purchased a can of compressed air to blow it out and that fixed it for me.