Why can't I increase the size of sda1 using gParted?

The extended sda2 partition is in the way. Do one of two things:

• If Gparted allows, move sda2 to the very right, and then you'll be able to expand sda1.
• Alternatively, delete sda2, expand sda1 by 2GB and then recreated your swap partition (an extended partition isn't required if you have 4 or less primary partitions).

Simplified answer from the previous post article:

In gparted:

1. Open sda2and resize it to fit all the unallocated space.
2. Open sda5 and move linux-swap all the way to the right, at the end of the disk.
3. Open sda2 again and resize it with the left handle to fit only sda5 size on right corner, leaving unnalocated space to the left.

4. gparted will then allow you to resize sda1 and increase its size, and apply changes.