running linux mint 18.1 - cinnamon; used gparted to make extended partition. Next made a logical partition inside new extended. Cannot mount new logical partition. "MOUNT" is always greyed out. Thank you very much for your help.

You must create a filesystem before you can mount it. E.g. with the "mkfs" command.

Thanks-will try it.

This is, of course, correct. I am surprised that the file system wasn't created and formatted when the OP created the logical partition in GParted ... Doesn't GParted usually have you specify the filesystem right away and format it when creating a new partition ?

Rickkkk-You are correct-file system IS created and formatted upon creating the logical partition. I've almost never had a problem creating partitions, but this is on a friend's machine, and I'm kind of stumped.Have deleted the newly made partition, and remade it several times, but always have same problem. I'm suspecting this may be due to his creating the extended partition himself(first time). Ordinarily, I would delete any and all partitions within the extended partition, and then start anew. However, he has Win10 and several other(?) partitions within the extended one.

Hi tosim ...

OK, if you're sure the filesystem is created and formatted within the logical partition you created, let's see if we can figure out why you can't seem to mount it.

Could you execute the following command in Mint and post the output ?

Thx ...

Rickkkk-Thanks so much for your assistance.
Here is the output of lsblk -fs
dave@dave-Lenovo-C540 ~ $ lsblk -fs
NAME FSTYPE LABEL UUID MOUNTPOINT
sr0
sdc5 vfat VOL 1 23AD-2980 /media/dave/V
└─sdc
sdc1
└─sdc
sdc6 vfat VOL 2 24DE-5680 /media/dave/V
└─sdc
sda2 ntfs Windows OS Win10 D4D675E8D675CB6E
└─sda
sda9 ext4 ae175389-f988-49c6-9469-3676edbf9681
└─sda
sda7 swap aeafd835-2ac1-4f44-8464-4d41b5061e9e [SWAP]
└─sda
sda5 ntfs Windows Storage C2F4FA78F4FA6DD3
└─sda
sda3
└─sda
sda1 ntfs System Reserved DA286C9B286C7901
└─sda
sda8 ext4 b37a522a-a993-42d9-b22d-60a6c314e6b3
└─sda
sda6 ext4 ae9714e8-d8d4-4728-9f02-802536a7d329 /
└─sda
dave@dave-Lenovo-C540 ~ $

I find use Disks(gnome disk utility) is a good app to check things out...

I've been a gparted user for a long time but have found issue with its use in recent times...

Still a top of the line app but sometimes can be a problem...

One other thing I have learnt over the years with partitioning, keep the partitions neat and cleanly setup, when you start doing stupid things and dont keep them in order, funny things can happen...

Logically speaking, it dont matter, but experience has shown otherwise...

Did you try a reboot before mounting? Sometimes that will make work.

Exactly which partition are you trying to mount?? Contrary to your original post, I don't see a configuration in your lsblk output showing one extended partition with one logical partition on either of the hard drives(sda and sdc). sdc has two logical paritions(sdc5 and sdc6) on the extended partition, sdc1, and on sda there are 5 logical partitions(sda5 thru 9) on the extended partition, sda3, with sda1 and sda2 being primary partitions. In addition, lsblk has sdc5 and sdc6 with the same mount point(/media/dave/V) and there is no sdb? To further clarify, could your run and post the output of the following:

If you're making partitions on a HDD with Gparted, you must make sure you're not on an OS on the same HDD/SSD.

Use Gparted from a different HDD/SSD.
Alternatively, just install a Linux OS onto a (cheap) USB flash drive.
Boot from the USB flashdrive, install Gparted onto it, and then manipulate the partitions on the HDD/SSD.

Gparted won't let you change partitions on the HDD because the OS you're using is on the same HDD. IMO.
Please send the output of This way, we can then see the disk drives, partitions and mountpoint.

Please put the output within the [CODE] icon which appears as '#' on your 'reply dialog box'.

Thank all of you for the assistance so far. The guy with the problem(not myself), will be tied up medically, for about a week starting today. Therefore, we have to take a break, and will not be able to handle the last few suggestions. Again, thank y'all for the assistance, and hopefully, when he gets back, we can continue this. Personally, if this was one of my machines, I would format entire hard drive, and start fresh.