Is it true that MM7, MM8 and MM9 will not work on Windows 10? I'm interested in the series but have only Win 10 available to work with.

It appears HOMM 1-5 and MM6 will work with Win10 (albeit some tweaking is perhaps required for HOMM4). But without MM7-9 an empty place is left. It's like reading a multi-book story but missing the last few books means you'll "never know what happend"...no closure.

I've been running MM6-8 without any major problems. Only real problem is running them in windowed mode. MM8 works fine, but it's hard to switch (if I want) to full screen mode. MM6 will only function in windowed mode in the upper-left corner of my main screen (I'm running 3 monitors). MM7 won't go into windowed mode at all. But other than that, everything seems to work.

I've been playing M&M 6 for weeks now, in Win 10. No problems.
Tried 8 briefly. No problems so far.
Tried 7 briefly. No problems so far.

I had some quality problems. But switched to Software control (Video 3D) and have had no problems. (M&M7)

I am running Windows 10 Education.
I played though all of them except 9 without any problems.

The issue with 9 is that it runs but opening a menu takes a full 30 seconds. This includes inventory and the escape menu. If you're patient enough, I guess it would be playable, but 9 is unanimously the worst in the series as well.

Thankyou everyone.

Other than that alt-tabbing back to Windows (for example to check a website for where you can find a trainer) results in serious graphical glitches, at least for me (Win 10 Pro, Nvidia GTX 780M). When alt-tabbing out of the game and back again, it seems like the game has been set to 256 colors (or less).
This applies to MM7 and MM8 (haven't tried 6 on my main computer yet).
Workaround: do not alt-tab. :-)

There's a solution, check this.

https://www.gog.com/forum/might_and_magic_series/might_magic_ix_fixes_all_in_one_place

Also google TELP patches but apparently the GOG version comes with them.

Or....maybe you could read at least the last post in the topic you're posting in or look through the forums for a solution to the MM9 problems? Given the fact I had just reposted the solution to the long loads right above your post, it seems ridiculous you didn't even try looking for it. But I'm mostly annoyed because I got a notifications someone replied to one of my messages and the link lead me here, but you're not quoting any of my posts, so you either clicked on the "reply" from my post and deleted the quotes, and it still alerted me, or it's a GOG bug since normally people only get notifications for replies and all replies in a topic they've created.

I don't know, and if you get annoyed because you received an alert, then get a life!

If you can't even say a 'thank you' for showing you how to fix the loading problems, after you didn't even bother to look through the thread if there was solution, then you should get your personality fixed.

I give a big thank you to the community, and to you @Green_Hilltop to help play those old game.

My post was merely to said that the game don't work natively on Win10, like others has noticed.

And no I didn't help to fix the problem, I was saying that there were a problem with the game.

Hope I made you happy today and wish you lots of fun with those game!