Gparted will not label an existing FAT32 partition

[Richard Owlett <rowlett@cloud85.net>]

Several years ago I purchased an external 1 TB USB connected 
drive for backups.
The base of the enclosure says it is a Seagate drive.
Partitions:
  #1 is ntfs 293 GiB [146 GiB used] labeled "FreeAgent GoFlex Drive"
  #2 is extended partition for remainder of drive
  #5 is fat32 62.5 GiB [31.5 GiB used] with no label


I successfully mounted partitions 1 and 5.  Both are readable and 
contain files from unknown Windows machines. On my Windows 
Desktop hardware C:\Documents and Settings\user\Recent indicates 
that it had been used on that machine back in 2011. There is 
similar evidence that it had been used on my Windows Laptop in 
2012. Neither machine reports files with "goflex" in filename 
{case insensitive search}.

I attempted to label partition 5 with Gparted, but the "Label" 
menu option was greyed out.
The "Label" option was available for partition 1. I had no 
problem creating partition 6 as fat32 and labeling it.

Any suggestions as to what the problem is?
Is there another option that would allow me to label the 
partition with no other effects on that partition?



TIA