Grundsätzlich can have two completely different meanings – see the quote from Philip Slotkin below.

This sign at Berlin Hauptbahnhof (formerly Anhalter Bahnhof) shows the problem of translating the word grundsätzlich into English.

This sentence is one of those that are not translated into English on the sign – no wonder!

Zur Verbesserung der Sauberkeit und aus Rücksichtnahme auf Nichtraucher ist das Rauchen in diesem Bahnhof grundsätzlich nicht gestattet.

(To keep the station clean and in consideration for non-smokers, smoking is in principle/as a general rule/absolutely not permitted.)

But it goes on to say

Bitte benutzen Sie die gekennzeichneten Raucherbereiche.
Please use the designated smoking areas.

It therefore appears that grundsätzlich here means ‘in general’ or ‘with a few exceptions’.

The sign doesn’t define what kind of Mitwirkung is envisaged and who constitutes Ihr Bahnhofsteam.

Actually grundsätzlich sometimes means ‘on the whole’ and sometimes ‘with no exceptions’.

A few years ago, Philip Slotkin wrote an article for Netzblatt, the publication of the ITI German Network, about awkward words, and here is what he wrote about grundsätzlich:

grundsätzlich
This is an interesting one because it can convey two almost diametrically opposite ideas: “always (with no exceptions ever)” or “in principle (normally, but with the possibility of exceptions)”. Sometimes the word, sonorous and important though it sounds, is best deliberately omitted: muss auch der beim EPA zugelassene und in die entsprechende Liste eingetragene Vertreter grundsätzlich eine von dem Anmelder oder den Anmeldern, für die er handeln soll, unterzeichnete Vollmachtserklärung einreichen: “even professional representatives who are included in the EPO’s list must submit a declaration of authorisation signed by the applicant or applicants on whose behalf they are to act” (omitted; the meaning is “always, without exception”).
But:
Das EPA kann grundsätzlich von jedem PCT-Staat als IPEA angegeben werden: “It is in principle open to any PCT State to specify the EPO as IPEA.” (That is, a PCT state does not have to do this.)

As Philip says, it is worth considering omitting the word altogether. But clients won’t always accept this. The number of times I’ve written ‘in principle’ in a translation and it sounded weird – but if the German text uses this silly word, it creates problems for the translator.

LATER NOTE: I’ve just had a similar problem with generell, and one suggestion which might also work for grundsätzlich is to translate it as ‘unless otherwise specified’.