Datomerkingen mangler; i så fall stopper mottakskontrollen.

Because Norwegian normally writes compound nouns as a single word.

Datomerkingen is made up of:

• dato = date
• merking = marking / labeling
• -en = the definite singular ending

So datomerkingen means the date marking / the date labeling. English often uses several words where Norwegian uses one compound noun.

The -en is the definite article attached to the noun. In Norwegian, the is often added as an ending instead of being a separate word.

Compare:

• en datomerking = a date marking
• datomerkingen = the date marking

So there is no separate word for the here because the definiteness is built into the noun.

Mangler is the present tense of å mangle.

In this sentence, it means is missing, not lacks in the English sense of needing something else.

That is an important Norwegian pattern:

• Datomerkingen mangler. = The date marking is missing.
• Produktet mangler datomerking. = The product lacks date marking.

So å mangle can work both ways:

• the missing thing can be the subject
• or the thing that lacks something can be the subject

In Bokmål, the present tense of many verbs ends in -r.

Here:

• mangler = is missing / lacks
• stopper = stops

Unlike English, Norwegian verbs do not change according to person:

• jeg mangler
• du mangler
• han mangler
• vi mangler

The same present-tense form is used for everyone.

I så fall is a fixed expression meaning:

• if so
• in that case
• if that is the case

It is best learned as a whole phrase. A word-for-word translation is less helpful than just recognizing it as an idiom.

Examples:

• Er det sant? I så fall må vi handle nå.
  Is that true? If so, we must act now.
• Hvis varen er skadet, stopper vi prosessen.
  If the item is damaged, we stop the process.

The semicolon links two closely related main clauses:

• Datomerkingen mangler
• i så fall stopper mottakskontrollen

A semicolon shows that the second clause follows logically from the first. It is stronger than a comma and tighter than a full stop.

You could also write:

• Datomerkingen mangler. I så fall stopper mottakskontrollen.

But the semicolon makes the connection especially clear in formal writing.

Because Norwegian main clauses usually follow the V2 rule: the finite verb comes in the second position.

If the sentence starts with i så fall, that phrase takes the first position, so the verb must come next:

• I så fall stopper mottakskontrollen.

If you start with the subject instead, you get:

• Mottakskontrollen stopper i så fall.

Both are possible, but once i så fall is moved to the front, stopper must come before the subject.

It is another Norwegian compound noun:

• mottak = receiving / intake
• kontroll = control / inspection
• -en = definite singular

So mottakskontrollen means something like:

• the receiving inspection
• the incoming inspection
• the intake control check

The exact English wording depends on the workplace or industry, but the grammar is straightforward: it is one compound noun in the definite form.

Grammatically, it means stops. The subject is mottakskontrollen, so the clause literally says:

• the receiving inspection stops

In English, though, you might sometimes translate the idea more naturally as:

• the receiving inspection is stopped
• the receiving inspection is halted

So the Norwegian is active in form, but English may prefer a passive wording depending on context.

It sounds fairly formal and technical. Words like datomerking and mottakskontroll are typical of:

• procedures
• quality-control documents
• warehouse routines
• production or food-industry instructions

A native speaker would find it completely natural in a professional or administrative setting, but less typical in casual conversation.