TP Link Archer C3150 user starting yesterday here...

Hi all, currently i facing some issues with my Archer C3150 router attaching with a 4tb external harddisk.

Previously it is working as a mini NAS for me without any problem, but when the harddisk close to 90% full recently, it start to freeze my router and i cannot access the harddisk and router setting page anymore until i restart my router and disconnect the external harddisk.

Anyone has experience this issues? Upgrade/downgrade firmware or delete some files for more free space doesn't help. It is annoying and really need some help here.