UbuntuMate won't install from NOOBS

I have tried putting Ubuntu-Mate on a NOOBS microSD but cannot get it to actually install and run Ubuntu-Mate. Got the file UbuntuMate.zip from https://ubuntu-mate.org/download/. When opened it has a directory \os\UbuntuMATE with what appear to be the appropriate files. I have copied the subdirectory UbuntuMate into the NOOBS os directory and then put the NOOBS SD into my RPi3. It allows me to select UbuntuMate for installation, but on launching it hags up with a multi-color square in the upper right corner of my monitor. I let is sit all night once just to see if it was slow in loading the first time, but no luck.

The other Paspberry NOOBS options load correctly and I got Ubuntu running by writing the image file directly to a microSD card.

Any suggestions?

How are you burning the image? I had a similar issue before on the Pi 3. I couldn’t pinpoint it exactly to what was causing it to not boot, but I was able to fix it by burning the Pi 3 image using the Mate disk restore. Go to System->Control Center->Disks. On the top right hand corner, click on the icon to see available options. Click on Restore Disk image. Make sure that the destination drive is SD card and not your hard drive or you will wipe the entire disk!

Does anyone has solved this problem? Install UbuntuMATE on NOOBS on a Raspberry PI 3

if your main PC is a windows machine you need win32diskimager from sourceforge,net
in short you need 2 programs to install and run correctly a different OS:
a disk imager program (this is different program from an program that deals with ISO files (unless it specifically supports .img files)
a specialty unzip program that supports unzipping of the correct formats of.zip/.7z/.xz like 7zip

NOOBS IS an OS like RASPIAN or UBUNTU, you cannot install UBUNTU on NOOBS, it is not an application but an Operating System.
You need to download the ARM based .img file, NOT an .iso file. Ubuntu builds that are NOT specific to your Pi platform (ARM7) will not install.
Once downloaded (and being careful with full attention) extract the zip/xz package with 7zip or another supported unzip program into a directory of choice.
RUN the win32diskimager.exe being CAREFUL TO CHOOSE THE CORRECT SD CARD DRIVE, and then click to navigate to where the OS disk .img file is located and click WRITE, it may take some time to complete. Once it completes do not just unplug the SD card, EJECT it from within windows or linux or whatever OS your using to WRITE the .img file to SD.
***CHOOSING THE WRONG DRIVE TO WRITE TO CAN CAUSE YOUR MAIN OPPERATING SYSTEM TO BE OVERWRITTEN AND BE ERASED SO USE CAUTION WITH A DISK IMAGER SOFTWARE!!!

insert the SD card into your raspberry pi and power it up. (you may need to use the HDMI output as my official pi 7" touch has the screen upside down)

NOOBS is NOT an OS, it is a bootloader.