I can vaguely remember several hints in various Star Trek episodes of one (or more?) turmoils in the past of the series universe, during which historical records were lost. This does not seem to affect periods that are common in the series and the real universe (e.g. it is clear that memories from World War 2 or the Apollo program survive), but it mostly has to do with records of either these turmoil periods themselves, or other periods in-between our (real) present and the series present & past, at least until the Federation was established.
The focus of the question is not the turmoils themselves, but the resulting loss of historical records, if any.
The question is inspired from the discussion in the comments of a recent thread, where a consensus does not seem to emerge.