Ik kwam er pas laat achter dat ik de verkeerde versie had geprint.

Erachter komen is a very common Dutch expression meaning to find out, to realize, or to discover something. It often suggests that you did not know it at first, and only understood it later.

So here it is not just a neutral fact. It implies a delayed realization.

The er points forward to the whole dat clause:

dat ik de verkeerde versie had geprint

In English, you usually do not need a separate word for this, but Dutch often does. You can think of er here as roughly meaning about it or that fact.

Compare:

• Ik kwam erachter dat... = I found out that...
• Ik kwam er later achter. = I found out later.

Because words have been placed between them: pas laat.

If nothing comes between them, you often see erachter written together:

• Ik kwam erachter dat...

But if something interrupts the combination, Dutch writes them separately:

• Ik kwam er pas laat achter dat...

So both patterns are normal; it depends on the word order.

Pas adds the idea of only or not until.

So pas laat means something like:

• only late
• not until late
• rather late

It emphasizes that the realization happened later than you might expect.

Kwam is the simple past of komen.

Dutch can often use either the simple past or the perfect here:

• Ik kwam er pas laat achter...
• Ik ben er pas laat achter gekomen...

Both are correct. The version with kwam can sound a bit more narrative or written, while the perfect version is also very common in everyday speech.

Because the printing happened before the moment of finding out.

Timeline:

1. I printed the wrong version.
2. Later, I realized it.

Dutch shows that earlier past action with the past perfect:

• had geprint = had printed

So:

• kwam ... achter = the later past moment of realization
• had geprint = the earlier past action

Because dat introduces a subordinate clause, and in Dutch subordinate clauses the verbs usually go to the end.

So:

• dat ik de verkeerde versie had geprint

Structure:

• dat = that
• ik = subject
• de verkeerde versie = object
• had geprint = verb cluster at the end

This is one of the most important Dutch word-order patterns to learn.

Because versie is a de-word in Dutch.

That gives:

• de versie
• de verkeerde versie

Also, the adjective gets -e here because it comes before the noun and the noun is definite with de.

Yes. Printen is a very normal Dutch verb, especially for computer-related printing, and geprint is its past participle.

So had geprint is completely natural.

You might also hear afdrukken:

• Ik had de verkeerde versie afgedrukt.

That is also correct, but geprint is very common in everyday Dutch.

Yes. A common alternative is:

Ik ontdekte pas laat dat ik de verkeerde versie had geprint.

That means almost the same thing.
The difference is that erachter komen is a very idiomatic everyday expression, while ontdekken is a bit more direct and slightly less colloquial in tone.