ablaufen
to expire
To reach the end of its period of validity or shelf life. Often refers to food, medication, or contracts.
Du kannst den Joghurt nicht mehr essen, er ist gestern abgelaufen.
You can't eat the yogurt anymore; it expired yesterday.

to expire / proceed / drain
Loading your saved state.
to expire
To reach the end of its period of validity or shelf life. Often refers to food, medication, or contracts.
Du kannst den Joghurt nicht mehr essen, er ist gestern abgelaufen.
You can't eat the yogurt anymore; it expired yesterday.

'Ablaufen' is a separable verb. The prefix 'ab-' goes to the end of the main clause. In subordinate clauses and in the infinitive with 'zu', the verb stays together.
Mein Reisepass läuft bald ab.
My passport expires soon.
Since 'ablaufen' describes a change (validity ends) or movement (water drains away), the perfect tense is always formed with the auxiliary verb 'sein' (to be).
Die Frist für die Bewerbung ist bereits abgelaufen.
The application deadline has already expired.
You can recognize the meaning of 'ablaufen' from the subject of the sentence. If it is a product or a contract, validity is meant. With an event, it is about the process. With a liquid, draining away is meant.
Der Film lief genau wie im Drehbuch beschrieben ab.
The film proceeded exactly as described in the script.
This meaning is often used for food, medication, documents, or contracts. Typical subjects are: der Joghurt (the yogurt), der Pass (the passport), das Visum (the visa), der Vertrag (the contract), die Garantie (the warranty), or eine Frist (a deadline).
Sein Arbeitsvertrag läuft Ende des Monats ab.
His employment contract expires at the end of the month.
To describe the course of an event, 'ablaufen' is often combined with adverbs. Common examples are: 'reibungslos ablaufen' (to proceed smoothly), 'nach Plan ablaufen' (to go according to plan), 'erfolgreich ablaufen' (to proceed successfully), or 'chaotisch ablaufen' (to proceed chaotically).
Dank der guten Vorbereitung ist die Konferenz reibungslos abgelaufen.
Thanks to the good preparation, the conference proceeded smoothly.
When a person actively makes sure that a liquid drains away, the construction with 'lassen' is often used: 'etwas ablaufen lassen' (to let something drain).
Nach dem Kochen lasse ich das heiße Wasser aus dem Topf ablaufen.
After cooking, I let the hot water drain out of the pot.
to apply / be valid
'gelten' and 'ablaufen' are clear opposites when it comes to validity. Something 'gilt' as long as it is valid or in effect, for example an ID, a ticket, or a contract. Something 'läuft ab' when this period of validity ends. They can be confused because both often appear with dates and deadlines. Pay attention to the direction: 'gelten' describes the time during which you are still allowed to use something; 'ablaufen' describes the end of that time.

Mein Pass läuft nächste Woche ab, deshalb brauche ich einen neuen.
My passport expires next week, so I need a new one.
Der Gutschein gilt noch bis Ende des Monats.
The voucher is still valid until the end of the month.