sicherheitshalber
just in case
Out of caution and in order to be on the safe side; to avoid a possible risk.
Ich habe die Daten sicherheitshalber auf einer externen Festplatte gespeichert.
I saved the data on an external hard drive just in case.

just in case
Loading your saved state.
just in case
Out of caution and in order to be on the safe side; to avoid a possible risk.
Ich habe die Daten sicherheitshalber auf einer externen Festplatte gespeichert.
I saved the data on an external hard drive just in case.

The word is made up of three parts: 'Sicherheit' (safety/security), the linking 's', and 'halber'. The ending '-halber' means 'because of' or 'for the sake of'. Literally, it means 'for the sake of safety'.
Nimm sicherheitshalber einen Regenschirm mit.
Take an umbrella with you just in case.
As an adverb, 'sicherheitshalber' (just in case) can stand at the beginning of the sentence (position 1), followed by the verb. It can also stand after the verb in the middle of the sentence.
Sicherheitshalber habe ich die Tür zweimal abgeschlossen.
Just in case, I locked the door twice.
'Sicherheitshalber' (just in case) is often connected with actions meant to minimize a risk. Typical examples are: taking something along, checking something, making a copy, or leaving earlier.
Wir sollten sicherheitshalber eine Stunde früher zum Flughafen fahren.
We should leave for the airport an hour earlier just in case.
precautionary
'vorsorglich' and 'sicherheitshalber' both express that you do something to avoid a possible risk. 'vorsorglich' often sounds somewhat more official or planned and fits well with measures taken in advance. 'sicherheitshalber' sounds more everyday and means roughly: better to be on the safe side, so that nothing goes wrong. The words are easy to confuse because both describe a cautious action. As a guide: for planned protective measures, 'vorsorglich' works well; for small everyday decisions, 'sicherheitshalber' often sounds more natural.

Sicherheitshalber speichert Tom die Datei noch einmal auf einem USB-Stick.
Just in case, Tom saves the file again on a USB stick.
Wegen des Sturms wurden vorsorgliche Maßnahmen am Bahnhof getroffen.
Because of the storm, precautionary measures were taken at the station.