Hi Leonard,
The techniques in first article you linked to are more for scenarios where the VM will not boot up. If I understand you correctly, your VM is able to boot successfully. I recommend you first create a snapshot of the disk, and then run chkdsk C: /f
If there is important data on the disk and you want to be extra careful, you could create a disk from the snapshot, attach this disk to a different VM, and verify that you are able to access any/all important data BEFORE you run chkdsk on your original still-up-and-running VM/disk.
I'm assuming the error is with C: but if it is different drive please substitute correct drive letter in command above.
Restart the VM so that it can work on the repairs and then once it has finished restarting connect to it and check to see if any message/errors are shown and things appear/function okay in general.
Please note that while it will likely fix any issues and you will be fine, there are no guarantees and this is why you use Azure Backup or other similar solution to back up disks that have important data periodically.
Please click Accept Answer and upvote if the above was useful.
Thanks.
-TP