The title of the question pretty much sums up my situation. I'm in Italy, I wish to travel to a non-Schengen European country. My visa for Italy is a multiple entry 'D' long stay. I have applied for the residence permit but haven't gotten it yet.
Can I leave Italy and re-enter without any problem?
The question is similar to this one here Can I leave the Schengen with my Type D Multi Entry visa from Spain
If your visa is still valid, I don't see any problem, the usual rules apply and you are exempted from the visa requirement to enter the Schengen area.
If your visa has special conditions or is not valid anymore and you are only staying on the basis of your pending application for a residence permit, then leaving and reentering is probably not allowed.
Answering my question in case it helps someone out in the future - despite getting conflicting info from a bunch of sources (Italian immigration included), I ended up leaving and re-entering Italy without any problems. I asked the official stamping my passport upon exit at the airport in Italy for advice and he said I was okay. Upon re-entering, the border official asked me if I had a permesso di soggiorno. I said I applied but haven't received it yet. No further questions were asked and he let me back in.
