case fans not spinning

[Garrett_39]

my case fan on the back is not spinning when i first start my pc ( its giving red led light)
when i restart my it spins?

 

[Vic 40]

Tried reconnecting the fan to the motherboard?
You could also try a clear cmos to see if there's something off in the bios.If yoyu changed settings like enabling XMP do so again after the clear cmos.