After Barclay's cat Neelix tries to eat Troi's ice cream, Barclay picks up the cat and places him in his lap, stroking his coat. When he puts the cat down, you can see that Barclay's uniform and pants are covered in white cat hair. Then he stands up while talking to Troi and he is still covered with cat hair. After the camera switches to Troi and then back to Barclay, his uniform is suddenly clean again.
Six security officers are shown to be pursuing Barcley, in the holodeck. However, when Barcley turns off the holodeck and they exit it, only two security officers are present.
In an exterior shot of Starfleet Headquarters, members of Starfleet are shown wearing the wrong uniforms for the era (wearing instead the uniforms that Voyager's crew are wearing).
The Galaxy displayed on screen when discussing Voyager's estimated flight path has an incorrect number of spiral arms.
When the camera pans across Admiral Paris' desk, you see a photo of Mr. Paris. It is clearly flipped because his communicator is on the wrong side of his chest. However, when Barclay and Admiral Paris are discussing Pathfinder and Admiral Paris glances at the photo just moments later, the communicator is suddenly on the correct side of the uniform.
When Barclay sneaks into the lab and says scan the area. And the computer gives the coordinates of the pulsar 227 by 41 mark 6, the closed captions says XYZ by X.
Barclay's holographic simulation of Voyager includes the former Maquis crewmen in their civilian clothes. However, the Doctor, when he was transferred to the Alpha Quadrant two years before, informed Starfleet of everything that had happened to the Voyager crew. Presumably, this would include the fact that the Maquis had been integrated into the Starfleet crew.
While in the holodeck, Reg is in engineering with B'Elanna. When security comes in to arrest Reg, B'Elanna fires here phaser at the security guards. She is firing a type II phaser circa 2366, used in Season 1 of Voyager, whereas the security officers are carrying type II boomerang phasers introduced in Season 2 and beyond.
When Barclay is on the holographic Voyager, while Pete and other security officers are chasing him, he issues commands to the computer to put up force fields, lock a jeffreys' tube door, and redirect communications to different sectors in the Delta Quadrent. How does the computer know which commands he is telling the holographic computer to do and which ones he is telling the real computer to do? Every command he says in the holodeck should only be registered by the holographic computer and not the real one.
After his arrest Barclay admitted to Admiral Paris that his plan didn't work, but really it had--he created a wormhole and transmitted through it. It turns out there was just a delay in hearing back, and it's odd Barclay didn't consider this, or consider that his team's projections on Voyager's location could be off. He should have told the Admiral the plan worked, but transmissions ought to be delivered to more sectors.