I guess is not strictly a gardening question

Some masking tape that was. Patent its use as an immovable and scratch resistant protective layer for almost anything. However, to remove it you'll probably have to resort to the scraper! I think you'll find it's the only way! Worthy

I am assuming that the offending masking tape is stuck to the window glass, Ginellie?
I would take a stanley knife and cut through the tape at the edge of the glass. Then get one of those stanley knife blade holders that hold the blade at right angles to the handle, in the manner of a paint scraper, and use it to scrape the tape off. There will still be old glue stuck to the glass and I would use water and a scouring pad to clean this up.
You must have bought very expensive, or very cheap, tape for it to stick like this :-(((. I have never had to take it off between coats.

Thanks Worthy, I think you are right. I have been a bit worried about a scraper because of scratching the glass (48 little panes)!

sometimes a razor blade can get under things cos it is so thin ~ its good for getting excess paint off so maybe it could work for your tape?

Thanks Bulbaholic. I thought I would make a really tidy job of the painting - wish I had just painted over the windows as it would have been easier to get the paint off. Never mind, I've learned masking tape is not for me. Come to think of it my children used to beg me not to make anything with sticky backed plastic.

I will try all suggestions because it looks so awful at the moment. Thank you.

Metal cannot scratch glass Ginellie! So don't worry.

Hi Ginellie, Happy New Year to you.
Rub it down with coarse sandpaper, followed by fine sandpaper. When painting again don't use masking tape, use vaseline on the glass only.

Thank you all so much for taking the time to reply to what, after all, was not really about gardening (I do keep some plants in there though over winter and use it to grow seeds in the summer as I don't have a greenhouse).G

Regarding Doctorbob's suggestion, don't do that on glass! Sandpaper will scratch glass, as will some plastic scrubbing pads--such as Scotch-Brite. I would use orange oil or WD-40 to remove the adhesive, if you have to, followed by rubbing alcohol to remove the oil.

Yes, it's ok TB I have explained it to Ginellie, it will scratch the glass, the only way I remove paint/varnish from glass is with freshly cut pieces of glass used as a scraper slowly with a gloved hand.

Sorry Db! I obviously misunderstood!

Great idea with the glass scraper, too.

I am grateful to you all and as soon as it stops raining I will be out there. Orange oil - that sounds lovely.