In my freighter, I'm hurrying up the stairs as usual, but today - lo! and behold! - everything looks at it was when I first saw it. The fleet command rooms, 10 storage rooms, the farm, everything gone.

The frigates are still there, and the inventory is as I left it the other day, including the tech upgrades. So it's really just the base.

Reloading/starting didn't do anything.
EDIT: Furthermore, I have no mods installed, and summoned the freighter several times, from various systems, also after reloading.
. . .
I have visited and expanded my freighter base before and after the update to v2.13. No problems. In fact the full-tile hydroponic trays finally snapped correctly!
. . .
A web search didn't reveal anything about such a thing (I probably asked the wrong questions).
. . .
Did you see this in your game? Any suggestions?
Thanks!

First thing to do with freighter malfunctions is to summon the freighter to a new place in space. Also you must remove all mods after an update because some of them may break your game.

Thank you! However, I have no mods installed, and summoned is several times from various systems, also after reloading.
I am going to use these two points to complete my question.

Probably not directly related to what you're experiencing, since I didn't have my freighter base completely reset - it's just the large room in the back, that's gone and I have Mordite neatly growing out of the floor where I never placed a planter.

If I try and build a Corridor or a Freighter Room in the general direction of what used to be the large room in the back of my freighter base, I can still see all of my equipment being there.

Happened around 2.11 / 2.12 in multiplayer. At least we had some fun experiencing different realities while our freighters shared the same coordinates :o)

Can't rebuild in-game, since I allways get 'Base out of range', no matter what. Multiple workarounds come to mind, all involve editing my save and / or buying a new freighter -- which I'll probably do in the near future.

Well, at least my ships are no longer on fire. That was something I couldn't workaround permanently.

I think I can flag this as the answer. As I see it, my freighter base is gone, and I am actively looking for a new one (it was good for its C-class, but it's time to move). This incident taught me to maintain a good, documented, backup series.
Thank you, I apprecciate it.

I don't really think that is the proper use of the [SOLVED] tag, as you didn't actually solve the problem, you just gave up and started over. It's fine to give up, but listing the thread as solved only serves to give false hope to anyone else reading the forum who has had the same problem.

Anyway, using the [SOLVED] tag for anything other than an actual fix for a problem diminishes the usefulness of the tag.

It must be said here that constructions aboard the freighter are not considered as 'bases', there is no base computer to delimit a claimed terrain, the position of the freighter is not fixed making any teleports impossible and the construction items are different although some of them are shared.

Plus, in all previous game versions it was shown that the base quests (with specialists like the overseer etc.) should NOT be launched on the freighter because it will break the missions in some cases. The Farmer is the only one that was shown to work correctly.
Although the 2.13 release has fixed bugs with the freighter, I assume that still many bugs are present, also the one falling in space and clipping errors with some constructions done.

If you build on your freighter, then have a Save Point placed in your vicinity and use it very often...
At some point you cannot progress because or you fall through the freigther in space, or you place a room that is invisible or you get stucked with other malfunctions. In that case you must reload your recent savegame and summon your freighter to a new location to fix the problem.

Tatwi has a point, and I have made it to myself. Sometimes, however, we have to accept a negative answer. "Your data is gone. Cope with it. Here is how." That's the proper answer I chose to flag as such. Sure, this may stir false hopes, and result in disappointment when opening the thread.

My problem could have been avoided by observing the following
Rule: Computers are brittle -- Maintain a line of backups.

So what i got out of this, is that im fine, because i use acronis to automate backups every 5 seconds for critical files that i consider important to me and windows backup to backup files every time the file is modified period. Well... thats not a reassuring thing, i only have 10tb of space and if its gonna be a crap ton of backups jesus crist. Then again the files are like 2-3mb everytime theres a edit.. so i'd have... well a lot of saves. Like i did back when starbound had constant failure issues.

I'm sooo happy: It happend again, and I had a backup, just a few hours old. [ SOLVED ] ;D