Learn Hardcore Russian: Иногда проблема решается просто: нужно открыть настройки и перезапустить приложение. - Sometimes the problem is solved easily: you need to open the settings and restart the app.

Решается is the 3rd person singular present tense, reflexive form of решать (imperfective). With -ся, it often has a passive or “happens by itself” meaning:

проблема решается ≈ the problem is solved / gets solved (in general, this is how it goes).

So the sentence describes a typical, repeated situation: Sometimes the problem gets solved simply…

Alternatives:

Иногда проблема решена просто… – Sometimes the problem is simply solved…
Here решена is a short passive participle (feminine). It usually means the problem is already in a completed, solved state. It sounds more like describing the final status than the general way you solve it.
Иногда проблему решают просто… – Sometimes they solve the problem simply…
Here it’s an active form with an implied “they,” which is less neutral and more about specific people doing it.

So проблема решается is a neutral, impersonal-sounding way to talk about how such problems are generally solved.

What exactly does просто mean here, and why is it not простая?

Просто is an adverb meaning simply / in a simple way / easily. It describes how the problem is solved.

просто (adverb): simply, just
- проблема решается просто – the problem is solved simply / it’s easy to solve the problem.
простой (adj. masc.), простая (adj. fem.), простое (adj. neut.): simple as a characteristic.
- простая проблема – a simple problem (the problem itself is simple).

If you said простая проблема решается…, you’d be describing a simple problem.
In the given sentence, we’re not saying the problem itself is simple. We’re saying the solution is simple, so the adverb просто is correct.

Why is there a colon : after просто? Could it be a comma?

The colon in Russian often introduces:

an explanation,
a result,
or a detailed clarification of what was just said.

Here:

Иногда проблема решается просто: – Sometimes the problem is solved simply:
нужно открыть настройки и перезапустить приложение. – this is the explanation of how it is simple.

So the structure is:
General statement → colon → explanation / example.

A comma instead of a colon would be wrong here in standard written Russian. A dash – could sometimes be used in similar constructions, but a colon is the most natural choice for “now I’ll explain how.”

What does нужно открыть mean, and who is the subject? Why is there no ты or вы?

Нужно открыть настройки… is an impersonal construction in Russian:

нужно
- infinitive = it is necessary to… / one needs to… / you need to…

There is no explicit subject like ты or вы. In this style:

The subject is generic (you in general, people in this situation).
It’s very common in instructions, manuals, and help texts.

More explicit versions:

Тебе нужно открыть настройки и перезапустить приложение. – You (singular, informal) need to open the settings and restart the app.
Вам нужно открыть настройки и перезапустить приложение. – You (polite/plural) need to…

Leaving out the pronoun makes it neutral and instruction-like, which is typical for technical/help texts.

Why are открыть and перезапустить in the perfective aspect, not открывать and перезапускать?

Открыть and перезапустить are perfective infinitives. Perfective aspect in Russian is used for:

single, complete actions,
the “result” of doing something.

Here we talk about one-time, complete steps:

открыть настройки – to open the settings (once, until they are open)
перезапустить приложение – to restart the app (once, until it has restarted)

Using imperfective would change the nuance:

нужно открывать настройки и перезапускать приложение – suggests you need to be opening and restarting (regularly, repeatedly) or describes a repeated/customary action, which doesn’t fit a one-time solution step-by-step instruction.

For instructions like “do X, do Y,” Russian almost always uses the perfective to emphasize successful completion of each step.

Why is настройки in the plural? Can you say открыть настройку?

Настройки is the plural of настройка.

In computer and phone language:

настройки (plural) usually means the settings menu / configuration section as a whole.
- открыть настройки – open the Settings (menu).

Настройка (singular) usually means one specific setting / adjustment:

Измени одну настройку. – Change one setting.

So:

открыть настройки – open the general Settings section (the normal phrase).
открыть настройку – open one specific setting, which would be unusual without further context.

That’s why the plural настройки is used here.

What is the difference between перезапустить and перезагрузить? Could I say перезагрузить приложение?

Both verbs imply restarting something, but usage tends to be:

перезапустить – to restart / relaunch (an app, a service, a process).
- перезапустить приложение – restart/relaunch the app.
перезагрузить – to reboot / reload (more common with devices, systems, pages):
- перезагрузить компьютер – reboot the computer.
- перезагрузить телефон – reboot the phone.
- перезагрузить страницу – reload a page.

Перезагрузить приложение is understandable and sometimes used (especially as “reload an app” in some technical contexts), but:

For ordinary users and normal instructions, перезапустить приложение sounds more natural and standard.

Can the word order be different, like Иногда просто решается проблема or Проблема иногда решается просто?

Yes, Russian allows flexible word order, but the nuance changes:

Иногда проблема решается просто… (original)
- Fairly neutral; slight emphasis on иногда (“sometimes”).
Проблема иногда решается просто…
- Emphasis a bit more on проблема; then we add that sometimes it’s solved easily.
Иногда просто решается проблема…
- This is possible, but sounds more marked/poetic or like spoken emphasis.
- Emphasis falls on просто (it just solves itself sometimes).

In standard explanatory text (like help instructions), the original word order is the most natural and neutral.

Why not use direct imperatives like Открой настройки и перезапусти приложение?

You can say:

Открой настройки и перезапусти приложение. – Open the settings and restart the app. (informal ты)
Откройте настройки и перезапустите приложение. – polite/plural вы

However, the original uses an impersonal, neutral instruction style:

нужно открыть настройки и перезапустить приложение – literally it’s necessary to open the settings and restart the app.

Differences:

Imperatives (Открой…) sound more like a direct command from speaker to listener.
Нужно + infinitive sounds more impersonal and instructional, like a manual or help text.

For documentation, FAQs, or general guidance, нужно + infinitive is extremely common.

Why is there no comma before и in нужно открыть настройки и перезапустить приложение?

In Russian, when two infinitives share the same auxiliary/particle, they are usually joined by и without a comma:

нужно открыть настройки и перезапустить приложение
Both открыть and перезапустить depend on the same нужно.

A comma could appear if:

the actions were quite long or complex and you wanted to emphasize a pause, or
they belonged to different parts of a larger sentence.

Here they are just two simple, parallel actions in a short instruction, so no comma is standard.