Why does my Lumia 550 keep restarting?

[Windows Central Question]

why does my lumia 550 keep restarting

Sometimes it restarts on it's own and sometimes when I press the power button, instead of going to sleep it closes down altogether

 

[charlatan1978]

Re: why does my lumia 550 keep restarting

Do you have any type of phone protector/cover on the device?
Perhaps something is catching the power button?

 

[Jeremy Siddons]

Re: why does my lumia 550 keep restarting

No, no cover and it can do it left on a table.

 

[charlatan1978]

Re: why does my lumia 550 keep restarting

Hi, just a few questions for you.
What build are you running?
Are you part of the Windows Insider programme?
Have you checked the store for updates and are they all installed?

 

[Jeremy Siddons]

Re: why does my lumia 550 keep restarting

The build is 10.0.10586.29, I'm not part of the Insider programme and it says it is up to date when I check for updates.

 

[charlatan1978]

Re: why does my lumia 550 keep restarting

Is it up to date when you check the store for updates?

 

[Jeremy Siddons]

Re: why does my lumia 550 keep restarting

Thanks for your help so far, I did reply earlier but I've just discovered that it didn't post because I had been logged out. I went into the store and then Downloads and Updates and checked for updates but it didn't show any. Is there anything else you can suggest?