For the purposes of research and study only

(This message is from the unaffiliated musescore-downloader project)

Musescore Pro ($6.99/mo) is required to download sheet music from musescore.com recently.
(However, a few months ago, it was free to download.)

The Musescore company said that this is about copyright and licensing, and they must pay the copyright owners.

Many kinds of music on musescore.com are already in the Public Domain, which means either the author posted them in Public Domain, or the author has been dead for over 70 years.
Do they need to pay those composers who died hundreds of years ago?
Update: sheets in Public Domain are able to be downloaded without Musescore Pro now, but we still need an account to access them.

Also, there are many sheet music authors on musescore.com who created their own songs and posted them under CC-BY-NC (Creative Commons Attribution-NonCommercial) License.
Is it illegal that they sell them for profit?
Note: Putting ads (to sell Musescore Pro) on the website also means that they use it to generate revenue.

This is absolutely not acceptable, and the only purpose is to profit from stealing.

There is an article on their website: Score download becomes a part of the Pro subscription

(System wide) To install musescore-dl as a system-wide script, navigate to the directory containing setup.py and install musescore-dl as a package: pip install .

(Script) To use musescore-dl as a local script, make sure you have the requirements installed by running pip install -r requirements.txt then navigate to the directory containing setup.py and run

python musescore_dl