How to fix Invalid Partition Table problem in Linux?

Question

linux

Good afternoon.
On one disk, which was divided into 2 parts, there were Linux Mint & Windows 10 and, accordingly, when booting via grub, you could select the system.
Today I demolished Windows 10 following these instructions -
https://lifehacker.com/how-to-uninstall-windows-or...

Keep Linux and Remove Windows

Keep Linux and Remove Windows

If you're the adventurous type and have decided to go to Linux full time, then your job is pretty easy. Instructions may vary by distro and your specific setup, but for the traditional Ubuntu setup, it should look something like this:

Insert a live CD or USB for your Linux distribution and start up its partition manager (like Gparted). Find your Windows partition in Gparted's menu—it'll be listed as an NTFS drive.
Right-click on that Windows partition and choose "Delete" from the menu. Your machine may have other Windows-related partitions as well, like "System Reserved" and recovery partitions. If you want, you can delete these as well (but make sure you have recovery discs handy if you're going to delete a recovery partition).
Right-click on your Linux partition and choose "Resize/Move." Resize it so it takes up the rest of the now-free space on your drive.
Click the "Apply All Operations" button in the toolbar to perform the selected tasks. It may give you a warning saying that your computer may not boot, but with most Linux instalations this shouldn't be a problem (though if it is, check out this article to fix it). This process may take some time, so let it be!

After rebooting the system, I get the following error:
Invalid Partition Table. After pressing enter, the system boots up successfully and everything works.
The BIOS is set to Legacy mode.
This command also shows Legacy mode

[ -d /sys/firmware/efi ] && echo "UEFI mode" || echo "Legacy mode"

Here is a screenshot from gparted


Here is the result of fdisk

Диск /dev/sda: 223,6 GiB, 240057409536 байт, 468862128 секторов
Единицы: секторов по 1 * 512 = 512 байт
Размер сектора (логический/физический): 512 байт / 512 байт
Размер I/O (минимальный/оптимальный): 512 байт / 512 байт
Тип метки диска: dos
Идентификатор диска: 0x747c164f

Устр-во    Загрузочный начало     Конец   Секторы Размер Идентификатор Тип
/dev/sda3                2048 468860927 468858880 223,6G             5 Расширенн
/dev/sda5                4096 468860927 468856832 223,6G            83 Linux

Why do I have 2 disk partitions? sda3 & sda5. And what kind of type - extended (extended)?
Now I'm downloading Boot-Repair Disk and I'll scan it. There may be something wrong with the /boot partition ... or it is completely missing)

Answer 1

Specifically, this problem is easiest to solve by throwing off those 80 gigs of useful information from this disk and splitting it again, humanly and without any logical volumes.
You can, of course, tinker with it in the same gparted, reducing it by half, creating another partition, dropping what you need on it, and so on, but it will take longer, and the risk of ruining the data will still remain.