partitioning - Gparted issue with Windows partitions (unable to read content) - dual-boot win7 ubuntu16.04

I have a dual-boot win7 and ubuntu 16.04 and wanted to shrink my windows partition. But when opening Gparted all the partitions are there but Gparted can't tell how much is used on my OSDISK (so can't resize). Plus i just noticed it makes them disapear from the sidebar in Files. Any idea how to solve this?

Thanks!

Gparted isn't the best tool for managing NTFS partitions. Instead, you should boot to windows and use Disk Management on Windows to resize the partition. Here's a guide for how to do it.

1. Go to the control panel and search "partition".

2. Click "Create and format hard disk partitions"

3. Right click the partition you want to shrink and click "Shrink
   Volume". Follow through the dialogs.