I don't know if this is generally known but I wasn't aware of it until a Velux repairer (kindly) told me that some of these windows manufactured  around 2001, see code below are replaced FOC, its a batch with code OOUE. I don't know if you contact them even if you have no cracks if they still replace them.

I returned from holidays to find a large crack in one of two attic windows, both window modules were replaced, what a service after 23 years. Apparently a vacuum forms between the two glasses and the inner one then can crack/shatter, the installer told me the glass thickness is now 8mm vs 4mm.

 

 

Edited March 29, 20242 yr by John Carroll

Yes I know someone who’s Velux shattered (in an en suite and luckily no one was in there) shower tray was damaged by broken glass, velux replaced the window and paid fir all the damage (I did post this a while ago)

Great service 

It’s not worth using the generic brands 

I dropped the glazed frame while fitting Velux sent me a new unit with just a half pallet postage to pay 

 

Though 23 years takes some beating 👏 

The Velux in my mums loft shattered last year because of this fault. It was installed around 20 years ago and replaced within a couple of months....which is fantastic service!