Ich klicke die Schaltfläche nicht noch einmal an, weil sonst dieselbe Datei zweimal in der Cloud gespeichert wird.

Because the verb is anklicken, which is a separable verb.

• Infinitive: anklicken = to click on
• In a main clause, the prefix separates:
  • Ich klicke die Schaltfläche an.

So:

• anklicken → infinitive
• ich klicke ... an → conjugated main clause

This is very common in German:

• anrufen → Ich rufe dich an.
• einkaufen → Wir kaufen heute ein.

If the verb is at the end of a clause or left in the infinitive, it stays together:

• ..., weil ich die Schaltfläche anklicke
• Ich will die Schaltfläche anklicken.

Die Schaltfläche means the button in a digital or interface sense, such as a button on a screen, app, or website.

It is a feminine noun:

• die Schaltfläche
• plural: die Schaltflächen

In everyday tech German, people also often say der Button, especially in informal speech or workplace IT contexts. But Schaltfläche is a good standard German word.

So these are both possible depending on style:

• Ich klicke die Schaltfläche an.
• Ich klicke den Button an.

The position of nicht depends on what is being negated.

Here, the idea is:

• I am not doing it again

So nicht goes before noch einmal:

• Ich klicke die Schaltfläche nicht noch einmal an.

That means the negation mainly applies to noch einmal = again / one more time.

Compare:

• Ich klicke die Schaltfläche nicht noch einmal an.
  = I’m not clicking the button again.

• Ich klicke nicht die Schaltfläche an.
  = It is not the button that I’m clicking.

• Ich klicke die Schaltfläche nicht an.
  = I’m not clicking the button at all.

So the sentence uses nicht in the natural place for not again.

Yes. Noch einmal means again or one more time.

In everyday spoken German, nochmal is very common:

• Ich klicke die Schaltfläche nicht nochmal an.

That is more conversational.
Noch einmal sounds a bit more neutral or careful in writing.

You may also see:

• erneut = again, anew
• wieder = again

But noch einmal works especially well when the idea is one more time.

Because weil is a subordinating conjunction. In German, a clause introduced by a subordinating conjunction sends the finite verb to the end.

Main clause:

• Ich klicke die Schaltfläche nicht noch einmal an

Subordinate clause with weil:

• ..., weil sonst dieselbe Datei zweimal in der Cloud gespeichert wird.

Notice that wird comes at the end.

This happens with many subordinating conjunctions:

• weil = because
• dass = that
• wenn = if/when
• obwohl = although

Examples:

• Ich gehe nach Hause, weil ich müde bin.
• Sie sagt, dass er kommt.

Sonst here means otherwise.

So the idea is:

• ..., weil sonst dieselbe Datei zweimal in der Cloud gespeichert wird.
• ..., because otherwise the same file gets stored twice in the cloud.

It adds the consequence that would happen if the speaker clicked again.

You will often see sonst used like this:

• Beeil dich, sonst verpassen wir den Zug.
  = Hurry up, otherwise we’ll miss the train.

In your sentence, sonst appears early in the subordinate clause, before the subject phrase. That is normal.

This is a classic learner question.

Strictly speaking:

• dieselbe Datei = the very same file, the identical one
• die gleiche Datei = the same kind of file or a file that is the same as another one

In real everyday German, many speakers do not keep this distinction very strictly, and die gleiche Datei is often used where strict grammar would prefer dieselbe Datei.

But in your sentence, dieselbe Datei is a very good choice, because the meaning is clearly:

• the exact same file would be stored twice

Examples:

• Wir haben dieselbe Jacke an.
  = We are literally wearing the same jacket.
  (logically odd unless sharing one jacket)

• Wir haben die gleiche Jacke an.
  = We are wearing identical jackets.

So here dieselbe Datei emphasizes the identical file.

Zweimal means twice.

It is an adverb, and here it tells you how many times the file would be stored:

• ..., weil sonst dieselbe Datei zweimal in der Cloud gespeichert wird.

German often uses words like:

• einmal = once
• zweimal = twice
• dreimal = three times

Its position here is very natural: it comes before the location phrase in der Cloud.

You could think of the clause roughly as:

• otherwise [the same file] [twice] [in the cloud] [is stored]

Because this sentence describes a location, not a direction of movement.

German often uses:

• in + dative for location: in der Cloud = in the cloud
• in + accusative for movement into something: in die Cloud = into the cloud

Here the file ends up being stored in the cloud, so the location is emphasized:

• in der Cloud

Compare:

• Die Datei ist in der Cloud.
  = The file is in the cloud.
  (location)

• Ich lade die Datei in die Cloud hoch.
  = I upload the file into the cloud.
  (direction)

So in der Cloud is correct here.

Because this is the passive voice.

• gespeichert wird = is stored / gets stored

The sentence focuses on what happens to the file, not on who does the storing.

Passive in German is commonly formed with:

• werden
  • past participle

Here:

• gespeichert = stored
• wird = is / gets

So:

• dieselbe Datei ... gespeichert wird
• literally: the same file ... is stored

An active version would need an agent, for example:

• ..., weil sonst das System dieselbe Datei zweimal in der Cloud speichert.
  = ..., because otherwise the system stores the same file twice in the cloud.

The passive sounds natural because the actor is unimportant or obvious.

In a subordinate clause, the finite verb goes to the end. In the passive, the finite verb is wird.

So the structure is:

• ..., weil ... gespeichert wird

Here:

• gespeichert = past participle
• wird = finite auxiliary verb

German often puts the participle near the end and the finite auxiliary at the very end in subordinate clauses.

Compare:

• Main clause: Die Datei wird gespeichert.
• Subordinate clause: ..., weil die Datei gespeichert wird.

This is normal word order for German verb forms in subordinate clauses.

Yes, that is possible, and it means almost the same thing.

Compare:

• Ich klicke die Schaltfläche nicht noch einmal an.
• Ich klicke die Schaltfläche kein zweites Mal an.

The first is more direct and everyday:

• not again

The second is slightly more formal or emphatic:

• not a second time

Both are correct.
Your original sentence sounds very natural.

Yes, it is natural and correct.

It sounds like something someone might say when explaining why they are being careful not to click a button again.

A few close alternatives would also sound natural:

• Ich klicke die Schaltfläche nicht nochmal an, weil sonst dieselbe Datei zweimal in der Cloud gespeichert wird.
• Ich klicke die Schaltfläche nicht erneut an, weil sonst dieselbe Datei zweimal in der Cloud gespeichert wird.

Your version is clear, idiomatic, and grammatically solid.