I have a new installation of slackware64-current with elilo boot loader.
So there is a FAT efi partition, which is in fstab

(this comes from the installation process).

I see this message at boot:

Is it harmful ?

Depends!
You can try this:
If errors occur, correct them.
Mount the partition with command:

fsck.vfat /dev/sdb1 gives

I choose 3)

You can also choose 1) and check again for fsck errors.

On my machine, the ESP doesn't like being unmounted by the general shutdown umount -a. It develops that "error" as a result. After correcting it, I suggest that you don't mount that partition automatically, only when you need it, and then unmount by hand. But if anyone can tell me why this makes a difference, I'd love to know.

2 members found this post helpful.

Same situation!
I would love to know too!

That partition is just finicky. I've seen that message (and been able to clean it with fsck) after power outages. (Yeah, I know, I should be on a UPS.)

Wait it is not unmounting when you restart? I thought this was addressed as I noticed similar behavior awhile back.

Maybe there's something slightly dicky with the kernel's vfat driver. I assume that any driver for a proprietary filesystem has to depend on occasional guesswork.

unmount /boot/efi
1) umount /boot/efi

2) run
fsck.vfat -n /dev/device_name
to check for errors

3) next run
fsck.vfat -a /dev/device_name
to fix vfat errors

4) edit /etc/fstab
comment out the reference to boot (EFI) partition

5) never see errors again

6) Mount /boot/efi partition before upgrading kernel

instead of removal, just add "noauto" to the fstab entry...
Enjoy!

3 members found this post helpful.

comment out: #
not the same as removal. Removing from fstab would be quite inconvenient.

whichever way: both works

Wouldn't it be great if EFI would alter standards to accommodate other file systems?... even ext2. Isn't it just like Microsoft to require SecurBoot but have an insecure file system as the most fundamental component excepting BIOS/UEFI?

Why is there even a partition at all? Why can't the firmware boot (EFI), like legacy BIOS. Of course on the other hand, I do have a separate /boot partition , but only because you can't boot / install lilo on XFS, so thats kinda different though (plus I am not using UEFI but legacy). Then again I don't know all the specifications of UEFI, and I guess somehow fat32 is considered "universal" these days, but even I myself had questions about this when it was introduced, since this brings back the old days of pre- NT days of Windows when you only had fat 12/16/32 to work with and any sort of improper shutdown (power loss), would result in constant errors and waiting for scandisk. We seem to have, reverted/returned/regressed to that period in time.

All the usb keys that you buy are formatted fat32 so any OS has to be able to read that format. I guess it really is universal.