This is my current partition table:

![screen0](https://i.stack.imgur.com/GeuKx.png)

In which `/dev/sda8` is the partition on Which I am currently running my primary OS - [Trisquel](https://trisquel.info) GNU/Linux (you can see it's mount point as `/`). The `/dev/sda1` is the primary partition containing Windows XP.

I want to resize `/dev/sda1` (Size:50GB ; Used 27.97GB) i.e. want to reduce it to 30GB (Split into 30GB + 20GB). So, I've first Unmounted `/dev/sda1`.

Now When I use **Resize/Move** option (from right-click menu) The following window appears:

![screen1](https://i.stack.imgur.com/POAWi.png)

The **problem** is that it doesn't allow to reduce partition! Why?(Because it is primary partition?)

And Finally **How can I resize (reduce/split) `/dev/sda1`?**

Note:- Gparted is running from Trisquel (GNU/Linux).
['https://unix.stackexchange.com/questions/184845', 'https://unix.stackexchange.com', 'https://unix.stackexchange.com/users/66803/']
My guess is that Windows XP places a master file table at the end of the partition, preventing you from resizing it. You should be able to move the master file table from within XP. Also maybe you need to defrag the Windows partition? And finally, are you sure you unmounted sda1? Run `df` in a terminal and make sure you don't see /dev/sda1 anywhere in the output, then close and reopen GParted
Try running a chkdsk and/or scandisk in Windows [to rule out bad sectors & other inconcistencies] then attempt to resize.