Устранение недостатков начнётся завтра.

Устранение is a noun meaning elimination, removal, or correction. It comes from the verb устранить / устранять.

Russian often uses this kind of noun-of-action in formal, technical, or bureaucratic style. So the sentence is built like:

Устранение недостатков = the correction/elimination of defects

A more everyday, more verbal version would be:

Завтра начнут устранять недостатки.
= They will start correcting the defects tomorrow.

So the original sentence sounds a bit more formal and impersonal.

Because устранение usually takes the thing being removed/corrected in the genitive.

So:

• недостатки = nominative plural, defects / shortcomings
• недостатков = genitive plural, of defects / of shortcomings

This is very common with verbal nouns in Russian:

• исправление ошибок = correction of mistakes
• устранение проблем = elimination of problems
• обсуждение вопросов = discussion of questions/issues

So устранение недостатков literally means elimination of defects.

Начнётся is the 3rd person singular future form of the perfective verb начаться.

So:

• начаться = to begin / to start
• начнётся = will begin

Because the verb is perfective, Russian uses the simple future form here, not a compound future.

Compare:

• начинаться = imperfective, to be beginning / to begin repeatedly
• начаться = perfective, to begin (as a completed starting point)

In this sentence, the idea is a single future event: the process will start tomorrow.

The -ся is part of the verb начаться.

There is an important difference:

• начать = to begin something
• начаться = to begin / to start (something starts)

So:

• Рабочие начнут устранение. = The workers will begin the repair/correction process.
• Устранение начнётся. = The repair/correction process will begin.

In your sentence, устранение недостатков is itself the thing that starts, so начаться is the natural choice.

Because the subject is устранение, which is a singular neuter noun.

Russian verbs agree with the subject in number (and in the past tense, also gender). Here:

• устранение = singular
• so начнётся = singular

Even though недостатков is plural, it is not the subject. It is part of the phrase устранение недостатков.

The core structure is:

Устранение — subject
начнётся — verb
завтра — time adverb

Here завтра is an adverb of time, meaning tomorrow.

It answers the question when?

• Когда начнётся устранение недостатков?
  Завтра.

In other contexts, завтра can behave more like a noun in expressions such as:

• до завтра = until tomorrow

But in your sentence, it is simply an adverb meaning tomorrow.

No. Russian word order is fairly flexible, although some orders sound more neutral than others.

The original:

Устранение недостатков начнётся завтра.

This is a neutral, natural order.

You could also say:

• Завтра начнётся устранение недостатков.
  This puts a little more focus on tomorrow.

• Начнётся завтра устранение недостатков.
  This is possible, but it sounds more marked or stylistically unusual.

So the original version is a very standard way to say it.

Yes, in many texts you may see начнется instead of начнётся, because Russian often omits the dots over ё in ordinary writing.

But the correct pronunciation is with ё, and ё is always stressed:

начнётся = approximately nach-nyot-sya

For learners, it is very helpful to keep ё whenever possible, because it shows both:

• the correct vowel sound
• the stress

So even if native texts often write начнется, you should understand that it is still pronounced начнётся.

Because Russian has no articles like a or the.

So Russian simply says:

Устранение недостатков начнётся завтра.

Depending on context, English may translate this as:

• The correction of the defects will begin tomorrow.
• Correction of defects will begin tomorrow.
• The elimination of shortcomings will begin tomorrow.

Russian leaves that information to context rather than using articles.

Yes, it sounds fairly formal, official, or technical.

That is mainly because of the noun-based style:

• устранение недостатков instead of a more everyday verb phrase

This kind of wording is common in:

• reports
• official notices
• technical documents
• workplace communication

A more conversational version might be:

• Завтра начнут устранять недостатки.
• Завтра будут исправлять недочёты.

So the original sentence is correct and natural, but stylistically it is more formal than everyday speech.

Yes. Недостатки is a broad word and can mean:

• defects or flaws in an object, product, or system
• shortcomings or weak points more generally

So the exact English translation depends on context.

For example:

• in manufacturing: defects
• in a report or plan: shortcomings
• in a person or method: weaknesses / faults

That is why устранение недостатков can often be translated idiomatically as correcting the problems or fixing the defects, depending on the situation.