Lost schematic symbol kicad after upgrading to V6

Ever since I upgraded to Kicad 6, many of my projects suffer from this phenomenon.

It is caused because some schematic items are named differently. For instans, an elco used to be a CP in kicad 5, now it is called C_POLARIZED. So al my elcos are now ??

And today I came across the bi color leds.

Besides replacing the items manually is this fixable perhaps?


When you upgraded to 6, did you install the libraries?

What did you do in the Rescue Dialog when you opened the schematic in KiCad V6 for the first time?

The root cause of this is that the graphics of a symbol was not stored in the project in KiCad V5. This has been an annoyance for a long time, and back then as a temporary fix the [Project]-cache.lib file was introduced. This file has an archive of the graphics of all library symbols used in the schematic, but quite a lot of people seemed to delete this file, as the schematic appeared to work without it and KiCad could reconstruct the schematic as long as the original libraries are present. If however both the original libraries and the [Project]-cache.lib file are missing, KiCad has no graphics to show for a symbol, and shows the [??] schematic symbol.

Luckily it can be fixed relatively easily with Schematic Editor / Tools / Edit Symbol Library Links. If your symbols are in some personal libraries and there is a problem with that library (for example it moved), you have to fix that first.

More good news is that KiCad V6 stores all data for schematic symbols in the schematic itself. From KiCad V6 on wards you should never ever see the dreaded [??] again.

Thank you for your answers.

Not used :flushed:

The problem also seem to be more persistant with the work laptop. My home pc does not suffer from this (most of the time). I am guessing that most projects were built on the home PC…

If your symbols are in some personal libraries

When you upgraded to 6, did you install the libraries?

Well that is the point, today I am merely complaining about the standard components like the elcos and leds. I think it is strange that such default components are changed for whatever reason causing bugs like this.

If it happens again I will try to use the Rescue Dialog.

Kind regards,


Whenever you open a schematic from the old format, you should see the Rescue dialog pop up. You must not ignore this or your symbols can be lost as shown! Instead you have to follow the prompt to remap your symbols.

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I guess one reason is that we are trained to click through many incomprehensible (some inentionally so like 100 page EULAs) dialogs and just press OK. If you would insert a “Format your c:/ drive before installing?” in some setup code, 90% of the users would press OK if it would be selected as default.
From the usability side, maybe this import dialog should be optimized such that safe defaults are applied (like rescue all components in this case) and the user is prevented (as far as possible) from damaging his design by unattentive OK-clicking.
On a side-note: Must not for german speakers with entry level english sounds like “nicht müssen” or “need not” - complete opposite meaning (one might even consider banning this expression in manuals optimized for a international audience, just like 1iI0oO for passwords printed in non-serif fonts)

Ignoring the remapping dialog is not the default though.

Interesting, but “must” and “must not” are some of the standard key words in IETF RFC 2119 that has a defined meaning, so I would think it is acceptable to use them according to the RFC 2119 definition even in international contexts.


We don’t do that here. KiCad has no “Are you really sure?” nuisance dialogues.

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I think I shouldn’t derail this thread any furhter. It was also not my intention to insult any GUI designer (sorry if I did), more some general wonderings about GUI design vs. audience type (think of designing for KiCad vs. Mentor Expedition). Also thanks a lot to Paul for the detailled explanation!

That’s not what I meant, others are doing it and people get used to click away dialogs. Just last week IT rolled out a low level driver update and the installer warned not to do a whole list of things (like running from a docking station) as it might permanently damage your system. A bit later I observed a colleague who did most of those things combined while running the installer. Asked why he said he had not even read the installer messages, just pressed OK.

Quite OK. I’ve actually asked why there aren’t more cautions/warnings in KiCad when you’re about to do something potentially “dumb”, and the development choice has been to err on the side of not badgering the user with dialog boxes. We have automatic backups. That’s good enough for me. :slight_smile:

We’re all getting notification fatigue as every website asks us about Cookies and GDPR and their Newsletter and wanting to know your GPS location and wanting you to sign up for Push Notifications. I too find myself just going click-click-click on this bull----. People have even written plugins to block Cookie notifications. :crazy_face:

I bless KiCAD for this. Using such a program infers some discipline and intelligence on the side of the user. I hate “nag”-messages.

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