An alternative to warehouses. The Memory Unit stores an unlimited amount of a single item type in one 3x3 building. The more items it holds, the more power it draws — storage is cheap to build and expensive to hoard.
Mine a loaded unit and it packs itself into an item carrying its contents. Place that item and everything comes back.
What this fork is, and what it will never be
A holding pattern, not a takeover. The original has no Factorio 2.1 release and an item duplication bug with three open reports. This is those two things fixed and nothing else.
The scope, stated as a promise:
- ✅ Factorio 2.1 support
- ✅ Bug fixes
- ❌ No new features
- ❌ No balance changes — same recipe, same technology, same power curve
- ❌ No redesign, no "improvements", no opinions about how the mod should work
If you want new things from a memory unit, this is the wrong mod, and it always will be.
It retires the moment notnotmelon publishes a 2.1 release. It gets marked deprecated and points back at the original, and you should switch. Because the prototype names are unchanged, switching either way is just swapping the mod — your existing units keep their contents.
This is a continuation fork
The original Memory Storage is by notnotmelon (Zachary Picco), released under the MIT license. All of the design, the code, and the artwork are his work. Source: **https://github.com/notnotmelon/deep-storage-unit**
The last release was 1.6.8 in December 2024, and there is no Factorio 2.1 build. This fork exists to fill that gap and to fix the duplication bug, nothing more. It is not endorsed by, affiliated with, or connected to the original author — he has not been asked, and this is not his work being represented as maintained.
If notnotmelon ships a 2.1 release, this fork retires. It will be marked deprecated and point back at the original. Take the original when that happens.
The duplication fix is lifted from Upsidedownfoxxo's deep-storage-unit-se-fox, also MIT, where it has been running since October 2025. Their fork is a Space Exploration rework of the same mod and worth a look if you play SE.
What changed
Runs on Factorio 2.1. The original's item-side API survived 2.1 unchanged, so this part is a version bump and nothing else.
Item duplication is fixed. A memory-unit ghost no longer carries stored contents, which is what made the exploit possible: anything that satisfied the ghost with an ordinary empty unit — a blueprint, an undo, a super-force-build, construction robots, a repair turret — restored the contents into the new unit while the packed item stayed in your inventory. Closes #24, #26 and #30.
The trade-off: blueprinting or undoing a loaded unit no longer carries its contents to the rebuilt unit — bots will build an empty one. Nothing is lost. The contents are still in the packed item in your inventory, and placing that item by hand restores them exactly as before. That workflow is gone deliberately: it is the same code path the exploit used.
Crash fixes. Mining, destroying, deconstructing or cloning a unit the mod had lost track of used to throw an unrecoverable error and take the save with it. Cloning a unit whose hidden power entity was already gone put its replacement on the neutral force, leaving it unpowered.
A GUI memory leak is fixed. Opening a unit's interface created a one-slot inventory that was never freed, once per open, for the entire life of the save.
No balance changes. Same recipe, same technology, same power curve, same everything. This is a bugfix set.
Full detail, including what is not fixed: see the FAQ tab.
Switching from the original: nothing to do
Just swap the mods. Disable Memory Storage, enable this, load your save. Your units keep working and keep their contents, including the unlimited amount held behind the visible slots.
That is worth spelling out, because it is not automatic for a fork in general. A Factorio mod's saved data is keyed to its internal mod name, and a fork has a different internal name - so a fork normally starts out knowing nothing about the units already in your factory, leaving them as dead boxes with a blank window.
This mod recovers them. Each unit publishes its total to a hidden constant combinator so the circuit network can read it, and a combinator is part of the world rather than mod data - so on first load the fork finds every unit it does not recognise, reads that signal back, and restores the stored amount. It reports in chat how many units it adopted and how much was restored.
Switching back to the original works the same way, because the original reads its own units the same way. Take a backup first regardless - it costs nothing and this is your factory.
One limit, stated plainly: a circuit signal is a 32-bit integer, so a unit holding more than 2,147,483,647 items is restored to that number. If that happens the mod says so in chat rather than rounding quietly. Below that ceiling nothing is lost.
Compatibility
- Do not run this alongside the original. Both define the same prototypes; the mod list declares them incompatible so Factorio tells you clearly instead of failing with a confusing error.
- Existing saves work, contents included - see "Switching from the original" above.
- Multiplayer: every player needs the same version, as with any mod.
- The fluid sibling is Fluid Memory Storage (Continued), which has the same fixes on the fluid side.
Reporting bugs
Bugs in this fork go to https://github.com/restjack/deep-storage-unit/issues. Please do not report them on notnotmelon's tracker — he did not ship this build.