[w8user]

Never tried to upgrade before, and today I got a message that Windows 10 is not available for my Lumia 435

[w8user]

After I got that screen, I reset the phone to rule out lack of space, but still no luck. I didn't insert any SD card

[w8user]

has anyone experienced this problem??

[chancooluk]

Is your 435 locked to a particular network? Or is it an unlocked variant?

[dov1978]

You have to do it using the Windows Upgrade Advisor app. I did mine about a year ago using this method and it's been fine since.

**edit

Just noticed your screenshot and it looks like that's how you were already trying to upgrade?
Weird if it's not working that way

[w8user]

Locked to T-Mobile

But in the past with other locked phone I had (different carrier), I got a message stating that I had to wait for the carrier's update, but no such message in this case

[libra89]

Locked to T-Mobile

But in the past with other locked phone I had (different carrier), I got a message stating that I had to wait for the carrier's update, but no such message in this case

This is very odd. In this case, I think T-Mobile decided not to approve the update.