verb
to occur, to happen, to seem
B1
vorkommen: separable strong verb meaning 'to occur' or 'to happen', and also 'to seem' in contexts like 'es kommt mir seltsam vor' (it seems strange to me). It uses sein as auxiliary (Perfekt: ist vorgekommen). Irregular: preterite kam, Partizip II vorgekommen.
Examples
Solche Fehler kommen selten vor.
Such mistakes rarely occur.
Das kommt oft vor.
That happens often.
Es kann jederzeit ein Problem vorkommen.
A problem could happen at any time.
Details
Mnemonics
Imagine phenomena 'coming forward' into view when they occur.
Think 'for-come' — things 'come' up before you (they occur).
Notes
Vorkommen is separable and uses 'sein' as auxiliary (z. B. 'es ist vorgekommen'). It is an intransitive verb and therefore does not normally form a true passive voice; passive forms are marked 'not applicable' in the conjugation table. The verb is not purely impersonal — it conjugates for all persons (e.g. 'Solche Fehler kommen selten vor').