IL-2 is notorious for having poor playback functionality. It is something that has plagued the game since the first title.
There are two types of game playbacks in IL-2. They have .trk and .ntrk extensions. Neither of them is a true recording of the action but simply a mission file with some extra code that the game replays as best it can when you watch the playback. The longer the video the more likely you will end up with a corrupted version.
The trk version is the one you get when you complete a mission and click the save .trk button and unfortunately it is the least stable of the two versions. The .trk version also only works using the patch level that was used to record it.
The ntrk version is the more stable of the two versions and is activated by using the "quick record" control. You must bind a key, key combo, or joystick button to the command in the Controls area for this record function to work. Once you use this option you are unable to use the save trk function at the end of game play. This .ntrk videos are compatible with all patch levels after it was recorded.
ex:
ntrk's recorded with patch level v4.09m should play with any patch level that is higher than v4.09m but it will not play in a v4.08m or lower version of the sim.
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