I installed ubuntu in sdb5 and windows 10 in sda1 many years ago. Also I asked someone else to help me installed an Apple’s system. I used grub to load the systems. Days ago after windows 10 was upgraded it cannot be loaded anymore. I can choose Windows 10 item in grub but it could not be loaded. There is only a black screen with a underscore flashing in the up left corner. Ubuntu can still be loaded and I can check the files in the disks.
I searched the solutions on Internet. I tried to delete some files in the disk to have more space; I tried to edit the 40_custom file but they did not work. Windows 10 still could not be loaded.
I tried not to reinstall the system.
Does anyone has any ideas? Why it happened? It has been working well for many years. Thanks!