Learn German: Obwohl vorschriftsmäßig, gefällt mir diese Lösung überhaupt nicht. - Although according to regulations, this solution does not please me at all.

This is an elliptical subordinate clause, meaning words have been left out because they are obvious from the context. The complete clause would be Obwohl sie vorschriftsmäßig ist, where sie refers to diese Lösung. Dropping the subject and verb makes the sentence more concise, which is quite common in written German.

Why does the main clause start with the verb gefällt?

Even though the first part is shortened and missing its verb, the entire phrase Obwohl vorschriftsmäßig still occupies the first position in the sentence. Because German requires the conjugated verb to be in the second position, gefällt must come immediately after the comma.

I sometimes mix up how to use gefallen. Why is it mir instead of mich, and what is the subject?

The verb gefallen (to please or appeal to) always takes a dative object for the person experiencing the feeling. The grammatical subject is actually the thing being liked, which in this case is diese Lösung. You can think of it literally as 'This solution does not please me at all'.

How does the suffix in vorschriftsmäßig work?

The word combines die Vorschrift (the regulation or rule) with the suffix -mäßig. This suffix comes from the noun das Maß (measure or extent) and is frequently attached to nouns to create adjectives meaning 'according to' or 'in the manner of'. Therefore, vorschriftsmäßig translates to 'according to regulations'.