slow boot

You can check what apps cause a slowing of your boot, in Linux, with this command:

systemd-analyze blame

You should see something like the following

systemd-analyze blame
3.115s NetworkManager-wait-online.service
1.980s fwupd-refresh.service
1.928s fwupd.service
[…]

To disable NetworkManager-wait-online.service, i.g., you can type: sudo systemctl disable NetworkManager-wait-online.service.

other possible causes

Check also if your UUID (of swap partitions, i.g.) are correct. This can be a cause of a severe slowing.


ssd slow (in Linux)

If your SSD has become slow, it could depend from the swap file: f.e. in fstab the ssd swap UUID could be wrong (after some partitions changes in your SSD).

You can fix this by giving to the swap partition the correct UUID.