# Rust Windows build: lazy\_static error\[E0463\]: can't find crate for \`core\`

**URL:** <https://travis-ci.community/t/rust-windows-build-lazy-static-error-e0463-cant-find-crate-for-core/8281>\
**Category:** Windows\
**Created:** [April 22, 2020, 1:37pm UTC](https://travis-ci.community/t/rust-windows-build-lazy-static-error-e0463-cant-find-crate-for-core/8281 "2020-04-22T13:37:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![dandavison](https://sea1.discourse-cdn.com/flex015/user_avatar/travis-ci.community/dandavison/32/2315_2.png) [@dandavison](https://travis-ci.community/u/dandavison)\
**Post date:** [April 22, 2020, 1:37pm UTC](https://travis-ci.community/t/rust-windows-build-lazy-static-error-e0463-cant-find-crate-for-core/8281/1 "2020-04-22T13:37:06Z")

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Hi, my Windows builds for Rust were working, but stopped working sometime in December 2019/January 2020.

Here’s the last successful build (Dec 12 2019): [https://travis-ci.com/github/dandavison/delta/jobs/266750525](https://travis-ci.com/github/dandavison/delta/jobs/266750525).

However if I rebuild now on the same commit, it fails: [https://travis-ci.com/github/dandavison/delta/jobs/322104619](https://travis-ci.com/github/dandavison/delta/jobs/322104619)

Here’s the first failing build (Jan 21 2020): [https://travis-ci.com/github/dandavison/delta/jobs/266751900](https://travis-ci.com/github/dandavison/delta/jobs/266751900)

The failing builds all fail with

```auto
process didn't exit successfully: `rustc --crate-name lazy_static C:\Users\travis\.cargo\registry\src\github.com-1ecc6299db9ec823\lazy_static-1.3.0\src\lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C debuginfo=2 -C metadata=f6b6078bac424eab -C extra-filename=-f6b6078bac424eab --out-dir C:\Users\travis\build\dandavison\delta\target\x86_64-pc-windows-msvc\debug\deps --target x86_64-pc-windows-msvc -L dependency=C:\Users\travis\build\dandavison\delta\target\x86_64-pc-windows-msvc\debug\deps -L dependency=C:\Users\travis\build\dandavison\delta\target\debug\deps --cap-lints allow` (exit code: 1)

```

```auto
error[E0463]: can't find crate for `core`
  |
  = note: the `x86_64-pc-windows-msvc` target may not be installed
error: aborting due to previous error
For more information about this error, try `rustc --explain E0463`.
error: could not compile `lazy_static`.

```

Can anyone point me towards getting Windows builds working again?

---

<div class="post-metadata">

**Author:** ![dandavison](https://sea1.discourse-cdn.com/flex015/user_avatar/travis-ci.community/dandavison/32/2315_2.png) [@dandavison](https://travis-ci.community/u/dandavison)\
**Post date:** [April 26, 2020, 8:10pm UTC](https://travis-ci.community/t/rust-windows-build-lazy-static-error-e0463-cant-find-crate-for-core/8281/2 "2020-04-26T20:10:43Z")

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This seems to have been due to a change in the Travis Windows build environment from stable-x86\_64-pc-windows-msvc to stable-x86\_64-pc-windows-gnu: my travis.yml was still requesting the former.

---

<div class="post-metadata">

**Author:** ![dandavison](https://sea1.discourse-cdn.com/flex015/user_avatar/travis-ci.community/dandavison/32/2315_2.png) [@dandavison](https://travis-ci.community/u/dandavison)\
**Post date:** [July 7, 2020, 4:22pm UTC](https://travis-ci.community/t/rust-windows-build-lazy-static-error-e0463-cant-find-crate-for-core/8281/3 "2020-07-07T16:22:07Z")

</div>

Now it seems to have switched back to stable-x86\_64-pc-windows-msvc.