Hello, I have a question about upgrading Nix. I watched Vimjoyer’s video and he said that to update, you should run:
nix flake update
and than
sudo nixos-rebuild switch --flake .#nixos
But I also heard somewhere else that you should delete the flake.lock file and then run:
sudo nixos-rebuild switch --upgrade --flake /etc/nixos/
Do these methods differ? Which one do you use? Why are they different?
Thanks. 
That will work, but it’s a bit of a hack; deleting your lockfile means that nix will regenerate it from scratch, which also means it will happen to grab the latest version of everything. Since currently there is no other persistent information in there, it’s probably fine. Nix used to have a --recreate-lock-file flag that basically did this, in fact.
Nonetheless, I’d recommend the former (i.e., nix flake update). Do keep in mind you need to run that command in /etc/nixos, likely also with sudo unless you changed permissions in that directory.
Additionally, the latter (deleting the lock file) seems like advice from someone who only knows nixos-rebuild exists and hasn’t figured out how to use nix yet, and hasn’t even read the nixos-rebuild help or doesn’t understand what the difference between channels and flake inputs is (since --upgrade makes no sense with flakes), so I’d suggest not listening any of their other suggestions.
Are you sure the first method updates everything?! Because I used the first method once and it didn’t update KDE, but the second method did. Is there a trick or something in the first method to make it update everything?! Or is it a normal mechanism that doesn’t touch some things? or i mistake ?!
What do you do yourself when you want to update and want it to update everything?
Thanks.
Yes, I’m certain. Updating your flake inputs doesn’t update KDE directly, it updates your copy of nixpkgs, which decides which version of KDE will be built.
Maybe there simply was no new version of KDE in nixpkgs at the time. Maybe your flake inputs are set up wrong. Maybe you have been using the stable branch and then switched to unstable, or maybe you made some other mistake along the way. Hard to say without seeing your code, and maybe a time machine.
I have a couple of years’ worth of weekly commits that do in fact update everything from this, too.
Thanks
Your update method is yet another different method. 
here’s my flake link, it’s very short. If you can, please take a look at it because I’m really not sure if there’s a problem with it or not. I feel like my config is correct, and I even asked an AI like Gemini 2.5 Pro and it said there are no issues.
Unfortunately, Nix doesn’t have comprehensive and complete documentation like Arch, which is why I can’t be sure if it’s really correct.
Thanks for your help and for taking the time to be active in the forum. I’ve never posted a question here where you weren’t one of the responders.
Thank you.
Heh, it’s not, I just ask Github to run nix flake update for me once a week.
There are a number of things I could nitpick and explain away as either pointless or clear misunderstandings, but as far as the topic of this thread goes, looks ok.
My guess is that you meant the plasma-manager input (rather than plasma itself), which likely just didn’t have a new commit when you attempted to update.
This happens pretty regularly on repositories that don’t see a lot of churn. For those it’s quite normal not to see an update, because you’re already up-to-date.
Nixpkgs is unusual because it’s so big; there will be updates roughly every hour, basically whenever hydra finishes building a new commit. I wouldn’t worry about nix flake update not doing anything unless nixpkgs doesn’t update for a day.
That aside, I’ll try to take some time to DM you with nitpicks, explanations and suggest better structure for your repo. I’ve done so quite a bit on here already, but I’ll sit down and try to write up a set of code smells and anti-patterns that I can just paste at people in the future 
One simple thing I would really suggest is to run nixfmt-rfc-style on all your nix files. It will instantly make things more legible, especially for people who didn’t write your code, and will also make it slightly easier to edit due to the foresightful design of line break behavior. You can create a .git-ignore-revs file if you want to hide the churn in your git history.
I also really recommend deadnix to scan for deadcode. nil can also help if you use an editor that supports LSP.
If you use flakes, using nix flake update is the intended method.
Deleting your lockfile is inadvisable if you can’t recover it via e.g. git reset.
I use first method and i got this error
for more information about error i use --verbose
amir@nixos /e/nixos [2]> sudo nixos-rebuild --verbose switch --flake .#nixos
debug: nixos_rebuild.process: calling run with args=['nix', '--extra-experimental-features', 'nix-command flakes', 'build', '--print-out-paths', '.#nixosConfigurations."nixos".config.system.build.nixos-rebuild', '-v', '--no-link'], kwargs={'stdout': -1}, extra_env=None
Using saved setting for 'extra-substituters = https://nix-community.cachix.org https://nixpkgs-wayland.cachix.org' from ~/.local/share/nix/trusted-settings.json.
Using saved setting for 'extra-trusted-public-keys = nixpkgs-wayland.cachix.org-1:3lwxaILxMRkVhehr5StQprHdEo4IrE8sRho9R9HOLYA= nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs=' from ~/.local/share/nix/trusted-settings.json.
warning: input 'stylix' has an override for a non-existent input 'home-manager'
debug: nixos_rebuild.process: captured output with stdout='/nix/store/dbh61pdd78k5i4yckfvs16lsxr8k7k66-nixos-rebuild-ng-0.0.0\n', stderr=None
building the system configuration...
debug: nixos_rebuild.process: calling run with args=['nix', '--extra-experimental-features', 'nix-command flakes', 'build', '--print-out-paths', '/etc/nixos#nixosConfigurations."nixos".config.system.build.toplevel', '-v', '--no-link'], kwargs={'stdout': -1}, extra_env=None
Using saved setting for 'extra-substituters = https://nix-community.cachix.org https://nixpkgs-wayland.cachix.org' from ~/.local/share/nix/trusted-settings.json.
Using saved setting for 'extra-trusted-public-keys = nixpkgs-wayland.cachix.org-1:3lwxaILxMRkVhehr5StQprHdEo4IrE8sRho9R9HOLYA= nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs=' from ~/.local/share/nix/trusted-settings.json.
warning: input 'stylix' has an override for a non-existent input 'home-manager'
these 87 derivations will be built:
/nix/store/zdi06d8rz9wbsn8hg4dd7k7l6qrhv5zw-python3.11-tkinter-3.11.13.drv
/nix/store/w8him1vqr57hfyv9y0crj50pdr1fs9ag-python3.11-matplotlib-3.10.5.drv
/nix/store/rd3a9nif9wqlii8awdp8aj70fbnbnf6k-python3.11-pytest-regressions-2.8.1.drv
/nix/store/pf604y0wrzzbkbgcrza69j2iqwdc23by-python3.11-markdown-it-py-3.0.0.drv
/nix/store/0qa56cflpjwkrvagbmhx4hglz9dp38c7-python3.11-rich-14.1.0.drv
/nix/store/5m9fr9bfdx3c69b8k4r9671spq98g6sm-python3.11-mdit-py-plugins-0.4.2.drv
/nix/store/1xd4fwfjz834n74hycjqs0kpa23nl4c7-python3.11-myst-parser-4.0.1.drv
/nix/store/2b4maaw05x4lnvlqk7gnrfz0prd3qjyn-python3.11-rich-argparse-1.7.1.drv
/nix/store/zg0gafczn9vdhq4bhibbalab72d59a2v-python3.11-executing-2.2.0.drv
/nix/store/g786giy0jllq6qfjqrjqi9m7dsamhxlg-python3.11-stack-data-0.6.3.drv
/nix/store/8fc9y6rl6fr0bfzhbmcba6a2bcv1a5j3-python3.11-ipython-9.4.0.drv
/nix/store/smp4zcm4bzqvqf9kfdf2yirfx3axhd2n-python3.11-python-dotenv-1.1.1.drv
/nix/store/f7rf0wjavp226fcifzshc9bkx9la79dn-python3.11-flask-3.1.2.drv
/nix/store/8bvnsp1wd0m8vpdqck4jrjncfvcp1x0l-python3.11-flasgger-0.9.7.1.drv
/nix/store/98yvikp4cd2n5ibm2268k9mnbrjii4jm-python3.11-httpbin-0.10.2.drv
/nix/store/y9a9g75db2zhc4bacl6wihg17x07kp42-python3.11-pytest-httpbin-2.1.0.drv
/nix/store/7m0nlpm62d0csf8ch422v1mqfizj7g6q-python3.11-httpcore-1.0.9.drv
/nix/store/2pcp5gsdsrb34323gb7yddwfdxggakgq-python3.11-httpx-0.28.1.drv
/nix/store/34j9c7h6jdc0a8lddhl6jj6xbkxsvi55-nvidia-settings-570.181.drv
/nix/store/wxdd0lxr18p9z722srj36llz3gs4g795-python3.11-requests-futures-1.0.2.drv
/nix/store/4j088wpkgrm7sp248hx2rwg334gjc8ch-python3.11-requests-mock-1.12.1.drv
/nix/store/53c56m80vfvpc18vr5zflrlgvn3d36qv-python3.11-requests-oauthlib-2.0.0.drv
/nix/store/gymzcp4ixl8swsvnv3r5s189rh6im135-python3.11-icecream-2.1.5.drv
/nix/store/dp3mzjqx35r8kd2wnxmwc44rci010830-python3.11-paramiko-4.0.0.drv
/nix/store/9nsyp8gls75fpapbg82pxgdfnpcks8xi-python3.11-proxy-py-2.4.10.drv
/nix/store/b5xwpmqkil3pq9cgji2ki003xm45c33p-python3.11-pytest-codspeed-4.0.0.drv
/nix/store/niq0bvdgk25q92ajmhvzgzr8raa8mqf4-python3.11-pydantic-2.11.7.drv
/nix/store/h2ck1m4khgqik5fksh0n72cgrg97kvyi-python3.11-versioningit-3.3.0.drv
/nix/store/j9079982m0pa93qyx4v0av43n4si3dma-python3.11-isal-1.7.2.drv
/nix/store/plmf9q29a17nv4bp3g1ffhh34ivdbq41-python3.11-propcache-0.3.2.drv
/nix/store/vfzpd0ajxhzhn49dfibs3ls27agsi6kx-python3.11-multidict-6.6.4.drv
/nix/store/wk32vj5vd8wqlfg4shm8lwzzva3648n1-python3.11-yarl-1.21.1.drv
/nix/store/y9fihqgz4yfn8qwzqqvkcygxndx2dh2j-python3.11-aiohappyeyeballs-2.6.1.drv
/nix/store/znvlm0nawlq4xxjhfb1nvzbgwd9jhi2g-python3.11-zlib-ng-0.5.1.drv
/nix/store/wf044iimqc0ijmi54a9glja0z1a3c5mf-python3.11-aiohttp-3.12.15.drv
/nix/store/i91z6gczdfq0l1il1hdqgpb5sx1lj81k-python3.11-aioresponses-0.7.8.drv
/nix/store/r4r9ly0gyid0gzh3k249lidg5k037kgx-python3.11-google-auth-2.40.3.drv
/nix/store/73b5nb00c1hapmlblifb7rvpkn2nvrh5-python3.11-kubernetes-18.20.0.drv
/nix/store/f0vs514aj58vglva4mpwncfpsq0spz5m-python3.11-influxdb-5.3.2.drv
/nix/store/j46y3rqmwn779f1j5zhx93nc0wbr3bsi-python3.11-cmd2-2.7.0.drv
/nix/store/s6ny3n3h7l0rgzpn63r39lmf165m38kw-python3.11-cherrypy-18.10.0.drv
/nix/store/4jy5aik1pmxdhjyby7kgcg58clnrb9nb-python3-3.11.13-env.drv
/nix/store/5jw8gqbg2xn7q4dlzndji59ybkq3gpwx-arrow-cpp-19.0.1.drv
/nix/store/id7r6iampjy90avv7k8yhjs01s0ac9aw-ceph-19.2.3.drv
/nix/store/9fmvvqznnd0vr8y8pzhv751lzfpq44yb-qemu-10.1.0.drv
/nix/store/4xgi47af0r72fcc5x8ajj88pmfsbkim2-qemu-10.1.0_fish-completions.drv
/nix/store/rpncfvvqk6wxjd15y0zmn3prcy15srdd-extest-1.0.2.drv
/nix/store/zbkflyghw651r777vsd8d95pddx5nkz2-steam-1.0.0.84-fhsenv-profile.drv
/nix/store/bs5jkxh54ak4pyyxzid82skksdnfj1w2-steam-1.0.0.84-fhsenv-rootfs.drv
/nix/store/4yqg7w94dvp4imnhavflsxk4wb5ppc95-steam-1.0.0.84-bwrap.drv
/nix/store/ranld6gwrdspznx8n28m8yf81ypg3wfh-android-studio-2025.1.3.7-linux.tar.gz.drv
/nix/store/y3sk7z9cn0gslssh9zs61jhfx0rfvnf4-android-studio-stable-2025.1.3.7-unwrapped.drv
/nix/store/5cksma0m6walnfgn240vx9pg8wyafcpx-android-studio-stable-2025.1.3.7.drv
/nix/store/mh3bs6kb6y59wh3n9cmhk6pmj1v531vm-steam-1.0.0.84.drv
/nix/store/w9br9fz2s0axj3p7qkp19g4xna7qdmwq-steam-run-fhsenv-profile.drv
/nix/store/h3p7wi2hi95cp03qbxcx6ic0brimv86j-steam-run-fhsenv-rootfs.drv
/nix/store/phk38aaz4dsamjilzw2nx3vr1kpaib5y-steam-run-bwrap.drv
/nix/store/wl6dxqvxsi0510mq5drkv0qlv56vrn87-steam-run.drv
/nix/store/zyvjmgm9agl5x00kcxcjjh2wdakfyvmc-google-chrome-140.0.7339.80.drv
/nix/store/93cw6q2dzz3n3fpx2wi184k4bq7w5406-system-path.drv
/nix/store/7bp47m5agbc43fbmpkkd2r2qzdkm2b2h-dbus-1.drv
/nix/store/s5vngwwhgzfaxgmbk2b8457djq67kr8z-X-Restart-Triggers-dbus.drv
/nix/store/w07h62jjvkacz5fc5y0whs088i2ad94d-unit-dbus.service.drv
/nix/store/6sp4mr11vc7nrggvqapdln1n09gkmy69-user-units.drv
/nix/store/a6m8a3cp8blxsfj43digpy5jmysyylcq-unit-dbus.service.drv
/nix/store/jrspvgc7yig21rnz4x3hc82spqjdq69s-unit-accounts-daemon.service.drv
/nix/store/a86zvc6jbarcfvw7na1dr3lg432qjyfw-X-Restart-Triggers-polkit.drv
/nix/store/sw9rwxs2is652fy1s3g05ba3587jzkac-unit-polkit.service.drv
/nix/store/cg80q9s0ldgd559g11xjnp441071zp2w-brave-1.81.137.drv
/nix/store/yyqyv4zdz4l8nj3wsmxhd56zjyjcsmn7-librewolf-bin-unwrapped-142.0.1-1.drv
/nix/store/cpfdvq7nili7anjk6gif5qszdkr7ja5p-librewolf-bin-142.0.1-1.drv
/nix/store/wm193vwlyppk872h9s3m01rhcdn281b8-home-manager-path.drv
/nix/store/c4z3wrhb9pvcm5nnmjmrqixpxjjjifvv-activation-script.drv
/nix/store/7kaa7j5kyc4m98kwhz1yb76vnc5ws20m-search.json.mozlz4.drv
/nix/store/fajyydh20jpj3qr246lg0cy50zyfjwbx-librewolf-native-messaging-hosts.drv
/nix/store/zn1sz06xyqsnb4jg1agyj50l2gy8d2ih-home-manager-files.drv
/nix/store/r43mx11fh8wjd3pg8p1xis33d35nsksk-home-manager-generation.drv
/nix/store/vlvk2x84qk0cwi5pgi4xp148nwi94hwa-unit-home-manager-amir.service.drv
/nix/store/6sxhv8906dd5d4cbv3kbicki1yac3475-system-units.drv
/nix/store/arawc6pxhizynv4liwckjqm48c4df1ll-google-chrome-140.0.7339.80_fish-completions.drv
/nix/store/aypdhwni916jqsfpnd23y7mfx656imsg-steam-1.0.0.84_fish-completions.drv
/nix/store/is89mgc371hzqkfrqkknk4yfk2snwp0p-android-studio-stable-2025.1.3.7_fish-completions.drv
/nix/store/whwp2ar07aki1i04gqnwlm9hgp1fqrla-nvidia-settings-570.181_fish-completions.drv
/nix/store/zq7f24r9m4dab613dxv2i0nbxsxm2hdf-steam-run_fish-completions.drv
/nix/store/f9wjvydfhlp3xkm90scc5r9m20nkbq5z-system_fish-completions.drv
/nix/store/9sciv5xgyna7y9dqji3r46ag42xxrqll-etc.drv
/nix/store/7g3sli6wav4jf9g82hf6k7fma67x8sjd-nixos-system-nixos-25.11.20250910.ab0f360.drv
building '/nix/store/zyvjmgm9agl5x00kcxcjjh2wdakfyvmc-google-chrome-140.0.7339.80.drv'...
building '/nix/store/34j9c7h6jdc0a8lddhl6jj6xbkxsvi55-nvidia-settings-570.181.drv'...
building '/nix/store/ranld6gwrdspznx8n28m8yf81ypg3wfh-android-studio-2025.1.3.7-linux.tar.gz.drv'...
building '/nix/store/5jw8gqbg2xn7q4dlzndji59ybkq3gpwx-arrow-cpp-19.0.1.drv'...
building '/nix/store/cg80q9s0ldgd559g11xjnp441071zp2w-brave-1.81.137.drv'...
building '/nix/store/rpncfvvqk6wxjd15y0zmn3prcy15srdd-extest-1.0.2.drv'...
building '/nix/store/s6ny3n3h7l0rgzpn63r39lmf165m38kw-python3.11-cherrypy-18.10.0.drv'...
building '/nix/store/yyqyv4zdz4l8nj3wsmxhd56zjyjcsmn7-librewolf-bin-unwrapped-142.0.1-1.drv'...
building '/nix/store/zdi06d8rz9wbsn8hg4dd7k7l6qrhv5zw-python3.11-tkinter-3.11.13.drv'...
error: builder for '/nix/store/zdi06d8rz9wbsn8hg4dd7k7l6qrhv5zw-python3.11-tkinter-3.11.13.drv' failed with exit code 1;
last 25 log lines:
> copying tkinter/filedialog.py -> build/lib.linux-x86_64-cpython-311/tkinter
> copying tkinter/font.py -> build/lib.linux-x86_64-cpython-311/tkinter
> copying tkinter/messagebox.py -> build/lib.linux-x86_64-cpython-311/tkinter
> copying tkinter/scrolledtext.py -> build/lib.linux-x86_64-cpython-311/tkinter
> copying tkinter/simpledialog.py -> build/lib.linux-x86_64-cpython-311/tkinter
> copying tkinter/tix.py -> build/lib.linux-x86_64-cpython-311/tkinter
> copying tkinter/ttk.py -> build/lib.linux-x86_64-cpython-311/tkinter
> running egg_info
> writing tkinter.egg-info/PKG-INFO
> writing dependency_links to tkinter.egg-info/dependency_links.txt
> writing top-level names to tkinter.egg-info/top_level.txt
> reading manifest file 'tkinter.egg-info/SOURCES.txt'
> writing manifest file 'tkinter.egg-info/SOURCES.txt'
> running build_ext
> building '_tkinter' extension
> creating build/temp.linux-x86_64-cpython-311
> gcc -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -I/nix/store/bcsfx7baf00f6bldlpshfsd6fnaxi8xx-libxcrypt-4.4.38/include -fPIC -I/nix/store/gf7b5x6vh2g3bq054lm5pj7zqzfx7vjc-python3-3.11.13/include/python3.11/internal/ -I/nix/store/gf7b5x6vh2g3bq054lm5pj7zqzfx7vjc-python3-3.11.13/include/python3.11 -c _tkinter.c -o build/temp.linux-x86_64-cpython-311/_tkinter.o
> In file included from _tkinter.c:61:
> /nix/store/zkvp5mrs2x620labv8gy506rrqdd9r35-tcl-9.0.1/include/tclTomMath.h:45:13: fatal error: tommath.h: No such file or directory
> 45 | # include "tommath.h"
> | ^~~~~~~~~~~
> compilation terminated.
> error: command '/nix/store/95k9rsn1zsw1yvir8mj824ldhf90i4qw-gcc-wrapper-14.3.0/bin/gcc' failed with exit code 1
>
> ERROR Backend subprocess exited when trying to invoke build_wheel
For full logs, run:
nix log /nix/store/zdi06d8rz9wbsn8hg4dd7k7l6qrhv5zw-python3.11-tkinter-3.11.13.drv
error: 1 dependencies of derivation '/nix/store/w8him1vqr57hfyv9y0crj50pdr1fs9ag-python3.11-matplotlib-3.10.5.drv' failed to build
error: 1 dependencies of derivation '/nix/store/rd3a9nif9wqlii8awdp8aj70fbnbnf6k-python3.11-pytest-regressions-2.8.1.drv' failed to build
error: 1 dependencies of derivation '/nix/store/pf604y0wrzzbkbgcrza69j2iqwdc23by-python3.11-markdown-it-py-3.0.0.drv' failed to build
error: 1 dependencies of derivation '/nix/store/1xd4fwfjz834n74hycjqs0kpa23nl4c7-python3.11-myst-parser-4.0.1.drv' failed to build
error: 1 dependencies of derivation '/nix/store/4jy5aik1pmxdhjyby7kgcg58clnrb9nb-python3-3.11.13-env.drv' failed to build
error (ignored): error: cannot unlink "/tmp/nix-build-arrow-cpp-19.0.1.drv-13/build/source": Directory not empty
error: 1 dependencies of derivation '/nix/store/id7r6iampjy90avv7k8yhjs01s0ac9aw-ceph-19.2.3.drv' failed to build
error: 1 dependencies of derivation '/nix/store/9fmvvqznnd0vr8y8pzhv751lzfpq44yb-qemu-10.1.0.drv' failed to build
error: 1 dependencies of derivation '/nix/store/4xgi47af0r72fcc5x8ajj88pmfsbkim2-qemu-10.1.0_fish-completions.drv' failed to build
error: 1 dependencies of derivation '/nix/store/93cw6q2dzz3n3fpx2wi184k4bq7w5406-system-path.drv' failed to build
error: 1 dependencies of derivation '/nix/store/7g3sli6wav4jf9g82hf6k7fma67x8sjd-nixos-system-nixos-25.11.20250910.ab0f360.drv' failed to build
Traceback (most recent call last):
File "/nix/store/dbh61pdd78k5i4yckfvs16lsxr8k7k66-nixos-rebuild-ng-0.0.0/lib/python3.13/site-packages/nixos_rebuild/__init__.py", line 364, in main
execute(sys.argv)
~~~~~~~^^^^^^^^^^
File "/nix/store/dbh61pdd78k5i4yckfvs16lsxr8k7k66-nixos-rebuild-ng-0.0.0/lib/python3.13/site-packages/nixos_rebuild/__init__.py", line 322, in execute
services.build_and_activate_system(
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
action=action,
^^^^^^^^^^^^^^
...<10 lines>...
flake_common_flags=flake_common_flags,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/nix/store/dbh61pdd78k5i4yckfvs16lsxr8k7k66-nixos-rebuild-ng-0.0.0/lib/python3.13/site-packages/nixos_rebuild/services.py", line 303, in build_and_activate_system
path_to_config = _build_system(
attr=attr,
...<9 lines>...
flake_common_flags=flake_common_flags,
)
my connection is good but i don’t know why i got this error
this is my flake
https://github.com/Amir-Hossein-Azimi/nix_Config/blob/9ac52aae6668cd3c8b21409745cb8843e62856b0/flake.nix
Please create new topics for new questions.
It seems like a faulty derivation of the dependency python3.11-tkinter-3.11.13.drv underlying qemu-10.1.0_fish-completions.drv, so I’d suggest temporarily disabling qemu to see if that fixes the problem.
thanks
and this is solution
https://discourse.nixos.org/t/error-after-update-flake-about-python3-11-tkinter/69328/3?u=amhoaz