I was using Windows 10 and Ubuntu 18.04 dual boot. And yesterday I was trying to create more space in Ubuntu partition. So, I tried to shrink space from the Windows partition using Windows disk management tool. But, it allowed me to shrink only 8 GB, and I needed more space (30GB). So, I used AOMEI partition assistant to shrink it. It went on a preOS mode and then after booting to Windows again I saw that it the required created 30GB space but formatted my Ubuntu partition too.
Edit
Oops, I found a silly mistake of mine. After shrinking through AOMEI I foolishly converted my EFI system partition from FAT32 to NTFS (using AOMEI). I converted it back again. And now I am able to boot to Windows normally, but not able to boot to Ubuntu, not even using the rEFInd rescue disk. Now, that's probably because of corruption in my linux-swap partition, but I am not sure.
Can you open Nautilus? If so, can you see the Windows 10 drives on the "Other Locations" tab? If you can see those drives, be sure to backup all your important data from those drives before you try something risky.
This will display the contents of EFI folder in your EFI System partition. Delete the ubuntu folder from here and also set Windows boot manager to boot Windows itself. To do so type following commands:
In case you cannot boot windows using the refind usb drive, Then go to the efi shell using the refind usb drive and press esc when the shell starts to skip and startup script. Then, type bcfg boot dump to display all the efi entries in your firmware. Look at the entries and note their numbers. Delete any Ubuntu related entry from here by typing bcfg boot rm XX.
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