Learn Hardcore Finnish: En löydä tiedostoa kansiosta, joten lähetän viestin pomolle. - I can’t find the file in the folder, so I will send a message to the boss.

Finnish normally drops subject pronouns because the verb already marks the person. En already means I do not, so (minä) is optional and usually omitted unless you want emphasis/contrast (e.g., Minä en löydä, mutta hän löytää = I can’t find it, but he can).

Why is it En löydä and not something like En löydän?

Finnish negation uses a special negative auxiliary verb (en/et/ei/emme/ette/eivät) that carries the person/number, and the main verb appears in the connegative form (a form that looks like the stem).
So:

minä löydän = I find (affirmative present)
minä en löydä = I don’t find / can’t find (negative present)

The main verb does not take the normal present ending in negative clauses.

Why is tiedostoa in the partitive, not tiedosto or tiedoston?

Because in Finnish, the object of a negative verb is typically in the partitive.
So En löydä tiedostoa literally uses the “partial/indefinite” object case, which is standard with negation.

What’s the difference between En löydä tiedostoa and En löydä tiedoston?

In most normal contexts, En löydä tiedostoa is the natural choice because negation strongly prefers partitive.
Using a “total object” form like tiedoston in a negative clause is unusual and would require a special context/interpretation (and often still sounds off). For everyday Finnish, remember: negative + partitive object.

What case is kansiosta, and why is it used?

Kansiosta is elative (ending -sta/-stä) meaning out of / from inside. Here it corresponds to English in the folder in the sense of “I can’t find it (when looking) in/from the folder’s contents.”

Related contrasts:

kansiossa (inessive) = in the folder (location)
kansiosta (elative) = from inside the folder (source/where you look through)
kansioon (illative) = into the folder

Is joten the only way to say so/therefore here?

No, but joten is a very common neutral option meaning so / therefore and it works well in written and spoken Finnish. Alternatives include:

niin (että) = so (that) (often more conversational; can imply a result)
sen takia / siksi = because of that / therefore (more explicit)

In your sentence, joten cleanly links “can’t find it” → “therefore I’ll send a message.”

Why is there a comma before joten?

In Finnish, you typically use a comma before coordinating/linking conjunctions like joten when they connect two independent clauses.
Here you have: 1) En löydä tiedostoa kansiosta
2) (minä) lähetän viestin pomolle
So the comma is standard.

Why is lähetän in the present tense if the meaning is about what I’m going to do?

Finnish often uses the present tense for near-future intentions, especially when the context makes it clear. Lähetän can mean I send or I’ll send.

If you want to be more explicit about intention/future, you can say:

Aion lähettää viestin pomolle. = I’m going to send a message to the boss.
Lähetän kohta viestin pomolle. = I’ll send a message to the boss soon.

Why is it viestin and not viestiä?

Viestin is a “total object” form (often described as accusative/genitive-looking in singular), used when the action is seen as complete/bounded: you send a message (one whole message).

Compare:

Lähetän viestin. = I’ll send (one) message. (complete unit)
Lähetän viestiä. = I’m sending messages / I’m in the process of messaging (more ongoing/partial)

What case is pomolle, and why does it mean “to my boss”?

Pomolle is allative (ending -lle) meaning to / onto. It marks the recipient: to the boss.
Finnish doesn’t require a word for my here; the context often makes it obvious whose boss it is. If you want to specify:

pomolleni = to my boss (-ni = my)
pomollesi = to your boss, etc.

Why use löytää (to find) rather than etsiä (to look for)?

They focus on different things:

etsiä = to search/look for (the process)
löytää = to find (the result)

En löydä tiedostoa emphasizes the failure to get the result (“it isn’t found / I can’t find it”). If you want to emphasize the searching effort, you could say:

Etsin tiedostoa, mutta en löydä sitä. = I’m looking for the file, but I can’t find it.

Why is it kansiosta (with -sta) and pomolle (with -lle)? Is this related to vowel harmony?

Yes. Finnish endings adapt to vowel harmony:

Words with back vowels (a, o, u) typically take -a type endings (e.g., -sta).
Words with front vowels (ä, ö, y) typically take -ä type endings (e.g., -stä).

kansio has a, o (back vowels) → kansiosta.
pomo also has back vowels → pomolle (the allative is -lle regardless of front/back, but many other endings vary like -ssa/-ssä, -sta/-stä).