In the past few weeks I've repeatedly heard of people losing their items when starting a manufacturing mission and aborting it mid-ways.
I've had this happen to myself in the past, too, I just simply forgot to report it. Now that it happened today to a guildmate again, I remembered it.

Process of how this happened:

I was going to build FFSA, started a mission and realized that I lacked Synthetic Silksteel, so I aborted the mission to go hunt Arklans while running Advanced Combat Practise.
When I came back with a stash of SSS, I realized that the 50cu of my normal Silksteel were missing along with the Ore involved in the building of one unit FFSA.
So I think the mission takes stuff from your inventory as soon as you run it but doesn't give it back if you decide not to build the item and abort.

Please fix this!

You aborted it. You have no one to blame but yourself for that. Though I do think that missions that are not time sensitive should have a "Mission Suspend" button.

Eh, I somehow cannot see how and why one should be blamed for aborting a mission and why they should not get their items back. You're making it look like a bad thing to abort a mission, however I don't see why it would be.
Imagine you are working on a big part and already took the mission but then you realize you lack 1 FFSA and 2 FCP or whatever... You couldn't go manufacturing cause you'd lose your stuff if you aborted. It's human nature to forget stuff, so you want to punish a guy who forgot to build 3 small items or miscounted numbers by taking all his stuff away for comitting that mistake?

I still believe this should be changed.

Or Or Or......

Now that the retarded system of having to launch and dock in order to fulfill a manufacturing mission has been fixed, how about a feature that pops up a window when you select a mission that let's the player know how many widgets they can actually manufacture and allow them to manufacture them all or as many as desired in one go. Also this window should show any how many units a player is short for a particular widget.

If you throw a chicken, carrots, potatos, and cabbage into a pot and heat it up for 15 minutes then pour it all out because you decided to go out to dinner, you don't get the fixings for your stew back.

Fluffy - A great idea Fluffy. Go and suggest that.

ARF - Doh. We don't cook here, we manufacture. Imagine you walk to the Station mechanics, give them the order and the mats and then you see you didn't hand them all the things. You could just go back to them, tell them you changed your mind and take the components with you again... There is no logical reason why you couldn't.

Because it's already on the assembly line?

I usually do a check to make sure I have all the items before taking a manufacturing mission (not claiming it's a perfect system).

After discovering you didn't have all the SSS, you could have not aborted the mission and gone out hunting Arklans.

If this were a second-tier or higher manufacturing mission, I would have been that much more careful to check and see that I had all the required components. If I did end up lacking something like FCP or FFSA, I would leave the mission active and contact some other players (again, not claiming the system's perfect).

As far as I know, this isn't a bug...

If it isn't a bug, it's STUPID.

For all of you trying to explain logically and "realistically" (ARF, Phaserlight) why it makes sense that you lose items in the way Sieger described -- you are completely forgetting that we are THOUSANDS of years into the future here. It is completely astonishing to me that there wouldn't be a more intuitive missions system that would prohibit you from taking missions you didn't have all the requirements for. If you don't have all the goods or requirements there should be a "are you sure you want to take this because you don't have xxxx" warning.

But explaining things in this game as they pertain to "real life" is a fools venture, and YOU ALL KNOW IT. Gameplay should be the top consideration and explanation for all things. This particular issue (and by extension the entire mission system) is severely lacking in what it could and should offer us, and it has a negative effect on gameplay. Hopefully the devs have it slated for an update sometime soon.

+1 to OP

Note that I'm not even claiming that the system should be left as is... just that what Seiger points out is actually the intended behavior under current implementation, hence this doesn't fit the definition of a bug.

This probably could have gone under Suggestions.

Actually, I don't know that it is the intended behavior. I aborted many a manufacturing mission during my build when I received the message screen that showed I did not have all of the necessary materials. Not once to my knowledge did I ever lose any of my raw materials. Maybe this was because I always manufacture from station inventory rather than ship inventory, but regardless, what the OP is about, is not the norm from my experience manufacturing.

Also, my 'suggestion' isn't new. It's been around a while in various forms :)

The fact is, this game isn't realistic. It is an arcade shooter in a nutshell. How would you explain going backwards when engine exhausts are pointed in opposite direction? Or non depleting asteroid resources? Or 100 kelvins (-173.15 celsius, - 279 fahrenheits) being super hot for mining?
So why go super realistic with manufacturing?

Couldn't have said it better, Rallen.

Maybe this was because I always manufacture from station inventory rather than ship inventory

Yes, that's why. The mission will not take anything unless the entire list is present in your station inventory, or you arrive at the station where you took the mission.

I agree entirely with Fluffy.

Manufacturing missions should pop up a box with a needed quantity list, a locally stored quantity list and a box at the bottom to do the mission only if all the stuff adds up to more than that needed.

Really, the thing in front of me is called a computer. It should be doing the adding up ...

Just had my first experience losing goods when manufacturing, so just to emphasise what I believe Sieger was trying to explain...

I have aborted many many missions with no ill affect until this evening. Tonight I aborted the mission to build the Milanar Computer twice. The first time, I was still docked at the station and realized that I had never moved the aggregator to the station.

The second time I ran the mission and realized I had used up all of my lanth finishing the MCA's. In my haste, and since I had another player waiting on me I launched to move another item to Latos instead since I was going to need to do some mining before I could finish building. We formed a group and while joining I discovered trying to join that I had not aborted the mission. So I aborted, joined the group and went on my happy way. Upon returning, I discovered that all of my inventory needed to build the computer was gone. (I put in a support ticked on this already)

I have to believe that losing goods has something to do either not being docked or having launched from the station after taking the mission and then aborting.

Edit: I did drop two items for transport, so it is highly likely that I docked once before aborting-which used to be the trigger to manufacture. Regardless, aborting before leaving the station seems to be safe from my experience, where leaving the station and or redocking incurs a loss if you abort.

I wasn't really trying to explain it - simply because I couldn't. I didn't know what exactly triggered the problem. So thanks for finding out!
This looks much like it isn't intended to happen.

If the mission takes your items and then you abort it, you currently lose those items. It's something we need to fix.