In most cases, such as the loop documented in Star Trek video transmission S02E13, the people in the loop may experience feelings of having done an action before, but have no actual recollection of it beyond those vague feelings.

However, there are exceptions to this, especially when the time loop is a result of technology. For example, in Stargate Video Transmission S04E06, three subjects who were caught in the time loop still retained their memories from loop to loop.

Please see the video transmissions referenced above for further information.

Continuous loops - This term refers to time loops that have not, or are unable to terminate. Although continuous loops are theorized to exist, none have been documented. It is theorized that if a timeline is locked into a loop then information from that timeline cannot exit. This theory is supported by what we know from other loops where information has only been possible to retrieve after the loop had been broken. Because of the inability to break the loop and continue on, space-time scientists classify this type of loop as the ending of a timeline.

Broken loops - These are the most commonly documented type of loop. "Broken" is referring to the end of the loop. Other dimensions have been now to refer to these as causality loops. A loop started, but the people inside were able to stop the cycle of events and free their timeline.

Aborted loops - This type of loop rarely occurs and often results in multiple alternate timelines. An aborted loop happens when a person or event from outside of the loop ends the loop. Please see video transmission S02E13 from E-ST1966 (Star Trek) for an example.