**System Information**
Operating system: Windows 10
Graphics card: Nvidia GTX 1070
**Blender Version**
Broken: 2.83-3.0
**Short description of error**
Over the course of two years that I have been using Blender on and off, I kept running into an issue where my custom hotkeys were removed from my keymap. This happened with hotkeys that I had been working with for months that worked perfectly fine (even just an hour ago at times). I have had dozens of instances where my custom hotkeys (but also those from the default keymap) were removed entirely without any other notable changes by me. Sometimes, they reverted back to the "factory reset" state, while I did not perform a factory reset. This is only for a few hotkeys at a time.
I suspect there are two causes for this:
**A)** When creating a keymap entry within a custom keymap, these entries are propagated back to the default "Blender" and "Industry Compatible" keymaps. When switching keymaps, other hotkeys custom hotkeys are assigned to the other keymaps or default keymap items become associated to the custom keymap. It occored for instance, after checking for new hotkeys within the default keymaps (i.e. the 3.0 knife tool modal hotkeys).
**Exact steps for others to reproduce the error**
1. Go to Edit > preferences
2. Create a new keymap with the "+" button.
3. Right click preferences > Create keyboard shortcut
4. Type in "Ctrl+K"
5. Go back to Edit> preferences
6. When switching keymaps from the dropdown, notice that any of the assigned hotkeys in the custom keymap also exist within the default Blender & Industry compatible keymaps.
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7. Upon saving preferences for the custom keymap, the default ones remain affected.
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I suspect that, when switching keymaps (e.g. to check the default modal hotkeys for the new 3.0 Knife tool), default keys are put back into the custom keymap, thereby reverting some of the entries within a custom keymap. This is the reverse behaviour displayed in the videos above. Just like switching from the custom keymap to the default, adds custom keymaps to the default keymaps.
**B)** Despite adding many additional items to my custom keymap over time — and leaving default ones unchecked so that I can always go back and look at the operators that were used — my keymap .py files are always between 485-497kb. I have noticed on multiple occassions that when default keymaps were removed from my keymap, that the size of the .py back-up that I created prior to loading the previous keymap, was always 485-487kb, so at worst about 10kb smaller. Could there be a limit to the keymap size, which causes Blender to arbitrarily remove hotkeys? There is no pattern that I could discover as to what was removed, it was neither the first, nor the last entry, nor always from the same category within the keymap. This makes it hard for me to diagnose what the cause is, as I have no clue as to what and if something was altered until something ceases to behave the way I configured it. Nevertheless, I can always confirm that I saved the keymap, since the keyboard shortcuts I added last, continue to function the way I assigned them prior to closing the application.
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//Some of the keymap items that were affected in the last day and a half, notice that all of these were set/ present in my previous install for over half a year ago//
```
A | To add objects in the 3d view > Reverted back to Shift + A
Mousewheel Up/ Down | Zoom in/ out within the node editor > Reverted back to scrolling vertically
C+W, C+E, C+R (C associated to a modifier button) | Clear location, scale, rotation > reverted back to the defaults for these commands
Ctrl+1/2/3/4/5/6 | Subdivision set > all but Ctrl+1 was removed from the keymap
Ctrl+T | Apply transformation > removed
```