Satmap SatSYNC is now working on my Windows 10 setup.
It seems that sometimes the upgrade to W10 will bring no SatSYNC problems and that sometimes there will be problems.

If SatSYNC fails after upgrading try the following:
Check in your programs and feature that Microsoft Visual C++ 2010 Service Pack 1 Redistributable Package MFC Security Update is installed.
If not download from here http://www.microsoft.com/en-us/download/details.aspx?id=26999
Ignore other versions of Microsoft Visual C++ which may be used by other programs.

For security in Windows your normal user settings should not include Administrative rights.
If this is the case on your system:
Temporally give your account Admin rights and then uninstall SatSYNC.
Check users for C:\Users\Your user name\AppData\Local\Satmap_Systems_Ltd
And delete them.

Re-install SatSYNC
It should work but you may have to right click and use ‘troubleshot compatibility’.
If it works remove Admin rights

When SatSYNC fails you get an error report on the desk top.
If at the end of all this contact Satmap help and send them the error report.
Finally I hope very few of you have to bother with this!

After more digging I found that Satsync does work on my laptop after upgrading to the lastest version on Window 10 which is 1511 10586-420
Check by pressin windows key + R and type winver in the Run command.
But it won't work on my destop, same version of W10, and so far Satmap have'nt found a solution which works.
Will let you know if when they do..

Windows 10 new version comes via Windows Update
some info here http://www.groovypost.com/news/windows-10-pc-update-kbtktk-build-10586-338-available-now/

I found that Satsync would not open after I changed to Windows 10. Satmap told me that it was not supported using Edge and to try it in Internet Explorer. That seems to work.

when I try to turn on Satsync nothing happens except I get an error report which I have sent to Satmap
They are trying to help but so far it does not work

Oh, maybe I spoke too soon. While typing the preceding post, SatSYNC appears to have acknowledged the S12 and again displays the list of routes & full data on my S12. Maybe it's just a matter of patience.
(Or maybe it was my blasting "Sister Ray" by Velvet Underground at it at the same time!!!)

I have just started SatSYNC on my Windows 10 PC; it started OK.
I then turned on my S12, then plugged it into the PC.
Initially SatSYNC displayed the list of routes but after a few seconds this list disappeared.
Now I can't get SatSYNC to acknowledge that the S12 is connected. No menus work; zilch!!
Looks like you're right Ray.
I shall now try it on another Windows PC....

I have been using satsync on W10 for a long time now without problems. I will check it again later to make sure it's still working.
What actually happens when you try to use it?

I have just upgraded to Windows 10 from W7 and everything works except Satsync, which I use after every walk.
Satmap advised me to go into programmes and features to check that .NET 3.5 was installed and it was. I am reporting back to them but I wonder if anyone else has had problems with Satsync on Windows 10. And more importantly found solution!
It may be relevant that there has been a major upgrade to W10 in htelast few days and I have the new version.