This KB is intended to supply resolution for when the VC port is stuck in "Initializing" State on Juniper Networks QFX5100 switches.

VC port is stuck in "Initializing" State on Juniper Networks QFX5100 switches.
 

{master:0}
user@switch> show virtual-chassis protocol adjacency 

fpc0:

Interface System State Hold (secs)
vcp-255/0/50.32768 44aa.502e.f7c0 Up 57

fpc1:

Interface System State Hold (secs)
vcp-255/0/50.32768 44aa.502d.3e80 Up 59
vcp-255/0/52.32768 44aa.502d.3e80 Initializing 59.

You need to reseat the VC-port and the same will establish the proper conversion and will be in "Up" state. This might need to be done on both ends of the VC-port link. There is no specific cause of this, it is considered to be a transient issue and may be not replicable.