Sometimes, in tatical, the game may seem to freeze up, but what is happening is its moving each and everyone of your ships based upon what you told the Fleet Leader to do.
It takes a while, but if you look closely at your ships, some of them will blink for a second. This meas that the computer is attempting to perform a move for you. what I suggest doing is to click on a ships and move it. Then if it does not move, walk away for a while and come back.
Fleets with large numbers of ships often take 3 to 5 minutes to complete a movement.
Hope this helps.
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"We've made too many compromises already, too many retreats! They invade our space and we fall back -- they assimilate entire worlds and we fall back! Not again! The line must be drawn here -- this far, no further! And I will make them pay for what they've done!" -- Patric Stewart as Captain Picard
UCP/TCO Ship Yards