An assembling machine cannot be upgraded to a higher level machine with a higher quality.
To reproduce:
1. Place an Assembling Machine 2.
2. In remote view, copy an existing Uncommon Assembling Machine 3
3. Attempt to paste the Uncommon AM3 in the place of ("on top of") the AM2
4. Note error: Assembling Machine 2 is in the way
If I select "Set Ghost Cursor" and select a new AM3 of Uncommon quality, I can upgrade the AM2 as expected.
[2.0.20] Cannot upgrade to quality Assembling Machine
Re: [2.0.20] Cannot upgrade to quality Assembling Machine
Thanks for the report. The official way to upgrade qualities of things is to use the upgrade planner and configure it to upgrade the quality as you want.
If you want to get ahold of me I'm almost always on Discord.
Re: [2.0.20] Cannot upgrade to quality Assembling Machine
Thanks for the tip. Good to know there is an alternative approach. To be able to copy and paste would still be useful for small ad-hoc edits that don't warrant the somewhat more involved (or at least intimidating – I've never quite mastered it) upgrade planner interface – though I appreciate you have a lot on your plates at the moment!