Time lock

A time lock was a mechanism whereby an event or series of events was rendered unreachable by time travel, blocking off a section of the Time Vortex. (AUDIO: 1963: Fanfare for the Common Men) It was thought impossible to pass through a time lock, but this was proven false; Dalek Caan did so, but at the cost of his sanity. (TV: The Stolen Earth) There were also other workarounds to enter a location blocked by a time lock, such as the use of a stasis cube to displace and freeze a moment of time outside of the natural progression of reality. With the event in question suspended from the actual flow of time, one could then enter it directly without needing to physically travel through the Time Vortex. (TV: The Day of the Doctor)

TARDIS component
The Doctor's TARDIS possessed a time lock. (GAME: TARDIS) When the TARDIS was suspended in space by the Great Intelligence, the Second Doctor wondered if the time lock had slipped. (TV: The Web of Fear)

By the Doctor
When the Doctor's TARDIS and the Master's TARDIS had each landed inside the other, the Third Doctor and each put a time lock on the other's TARDIS to prevent escape. (TV: The Time Monster)

In the New Earth System, the Fourth Doctor created a time lock to trap the Daleks and the Wereloks outside of the TARDIS. (COMIC: The Dogs of Doom)

When the Doctor used the Moment at the end of Last Great Time War, the entire war was time locked. (COMIC: Don't Step on the Grass)

By Time Lords
In ancient times, the Time Lords used time locks to hide their secrets and misdeeds. When Skagra used The Worshipful and Ancient Law of Gallifrey to access Shada, Romana hypothesised that they were passing through a time lock. (PROSE: Shada)

Matthias quarantined Time Lords infected by the Dogma Virus in time-locked facilities. (AUDIO: Ascension)

Dalek Caan overcame the lock on the Time War after making an emergency temporal shift and travelled back to the Gates of Elysium to save Davros. The process flooded Caan's mind with total knowledge of the past, present and future, driving him insane. (TV: The Stolen Earth) The only other things capable of breaching the time lock were those that were already in place, like the signal that had been transmitted back through time into the Master's mind and, on at least one occasion, very small objects, such as the White-Point Star diamond sent by Rassilon to follow the signal in 's head. (TV: The End of Time)

When the Tenth and Eleventh Doctors confronted the War Doctor as he prepared to use the Moment, the Tenth Doctor noted that they shouldn't have been there as the events should be time locked. The Eleventh Doctor deduced that something let them through. A comment by the Moment's interface implied that it was she herself who had let them through. (TV: The Day of the Doctor)

By Torchwood
Another sort of time lock, created by Torchwood 3's resident genius Toshiko Sato, was designed to freeze the Torchwood 3 Hub in a bubble in time. It was at the same time impenetrable but inescapable. The time lock was either shut down or damaged when a Dalek trapped at the edge of the bubble was blown up by the Meta-Crisis Tenth Doctor. (TV: Journey's End)

By Daleks
Led by a new Emperor Dalek, the Daleks of the New Dalek Paradigm planned to remove Gallifrey from existence and become the new Lords of Time. They used a piece of the Eternity Clock to put a Time-Lock around a large part of London in 2106. Once they perfected their Time-Lock technology, they planned to use it to put temporal bubbles around other planets, making them unstoppable. However the Eleventh Doctor and River Song stole a Time Capsule from the Silents to break through the Daleks' Time Lock. They infiltrated the Emperor's Flagship managed to take back the piece of the Clock. (GAME: The Eternity Clock)

By Ace
At the Time Lord Academy on Gallifrey, Ace was given the planet of Talmeson to watch over. The planet was eventually wiped out by the Daleks. That was when she decided to wipe out the Daleks by time locking Skaro using an Omega device. When the Doctor found out that Ace went missing, he sent Bernice Summerfield to find and stop her. (AUDIO: The Lights of Skaro)

By the Weeping Angels
The Weeping Angels could create a sort of time lock, such as the one that separated the Doctor from Amy Pond and Rory Williams in New York (TV: The Angels Take Manhattan).

Expression
The Vist looked down upon the "time-locked races" in reference to their natural time travel ability. (AUDIO: The Forbidden Time)

Last of the Time Lords
After the events of the Time War, the Doctor never sees any other Time Lords except for versions of himself and the Master, and under extraordinary conditions, Rassilon. (TV: The End of Time) This may be due to a time lock.

Time Streams
All individuals had personal time streams that they could not travel into, much like a time lock; however, this only applied to the time stream of a particular individual, and it was more easy to cross. (TV: The Wedding of River Song)