racket / racket/racket

"API-MS-WIN-CRT-RUNTIME-L1-1-1.0.DLL" startup error on Windows Arm

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arch:aarch64 platform:windows
Dominant language
Racket
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Forks
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Avg merge
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Merged PRs (30d)
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Description

After a February, 2026 update of Windows 11 on Arm, Racket fails to start and reports an error related to "API-MS-WIN-CRT-RUNTIME-L1-1-1.0.DLL".

Commit 874a860656d2db5dbdc86bbe799391d6ae59a7c5 addresses the problem by directly loading "ucrtbase.dll", instead, but this repair (if it is the right one) will become available in a regular release only with version 9.2. Meanwhile, users with updated Windows Arm installations can use the x86_64 build or try a snapshot (https://snapshot.racket-lang.org/) for 2026-02-26 or later.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing commit 874a860656d2db5dbdc86bbe799391d6ae59a7c5, which addresses the Windows Arm startup failure, and compare it with the issue's DLL error. Verify whether the repair is present in the relevant build and whether affected Windows Arm users can start Racket without the error.

Written by the indexing model from the issue text.

Assessment

Domain
operating-systems
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
35/100

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