Breakdown of Sie müssen sich einloggen, sonst löschen wir die Daten.
Sie
you (formal)
wir
we
müssen
to have to, must
löschen
to delete
Questions & Answers about Sie müssen sich einloggen, sonst löschen wir die Daten.
Why is the word order sonst löschen wir instead of sonst wir löschen?
The word sonst (otherwise) is an adverbial connector. This means it counts as the first block of information (Position 1) in the new clause. Because standard German main clauses require the conjugated verb to be in Position 2, the verb löschen must come immediately after sonst, which pushes the subject wir into Position 3.
Why is there a sich in the first part of the sentence?
In German, the verb for logging in is reflexive: sich einloggen. You are literally saying that you must log yourself in. Since the sentence uses the formal you (Sie), the matching reflexive pronoun is sich.
einloggen is a separable verb. Why isn't the prefix ein separated here?
It stays attached because of the modal verb müssen (must). A modal verb in Position 2 forces the second verb to the very end of the clause in its full, unseparated dictionary form. Without the modal verb, it would split normally: Sie loggen sich ein.
The English translation says we will delete, but there is no future tense word like werden in the German sentence. Why?
German frequently uses the present tense to talk about the future, as long as the context makes the timing clear. Saying sonst löschen wir (literally: otherwise we delete) is the most natural way to express a future consequence like this in German.