Positron fails to start R

[BernardForgues]

Hi,

When launching Positron 2025.11.0 build 234 on a Mac BookPro (MacOS 26.1 (25B78)), I get the following error message:
R 4.5.2 failed to start up (exit code -1)
The process exited abnormally (signal: 6 (SIGABRT))
The issue is not with R, which works perfectly with RStudio.

I filed the issue on Positron https://forum.posit.co/t/positron-fails-at-startup/209308 and was redirected here.

Also, following advice there, I tried to upgrade to the latest daily build, but got the same error message.

Thanks for your help!
Bernard

[lionel-]

I can't reproduce with either the Positron version you mentioned or a newer one.

Could you please provide the logs? https://positron.posit.co/troubleshooting.html#python-and-r-logs

I'm interested in particular in a line looking like this:

[R]   2025-12-01T11:23:43.802656Z  INFO  Successfully opened R shared library at '/Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libR.dylib'.
[R]     at crates/harp/src/library.rs:30

Hopefully there will be a backtrace too, the abort is likely from our panic hook.

[lionel-]

oh and please provide the information in "About Positron".

Here is the R preamble you provided in the other thread:

R version 4.5.2 (2025-10-31) -- "[Not] Part in a Rumble"
Copyright (C) 2025 The R Foundation for Statistical Computing
Platform: aarch64-apple-darwin20

[BernardForgues]

Hi, thanks for your help.
The "About Positron" info is as follows (I have just reinstalled it):
Positron Version: 2025.11.0 build 234
Code - OSS Version: 1.105.0
Commit: 807acdfca108da6b9b2d96452fe047238da1bd9f
Date: 2025-10-31T23:02:00.803Z
Electron: 37.6.0
Chromium: 138.0.7204.251
Node.js: 22.19.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 25.1.0

Apologies for my ignorance, but I couldn't locate the logs. The web page says to "Run the Output: Show Output Channels command", but given that the console doesn't start, it doesn't accept any command…
I checked in the Library folder, but to no avail.

[lionel-]

You can use Cmd-Shift-P to run Positron commands from the command palette.

[BernardForgues]

Oh, OK. Thanks!
The log is attached.
Perhaps the line you're interested in is:
[R] 2025-12-02T17:15:44.669755Z ERROR Panic! In file 'crates/harp/src/library.rs' at line 23: The R shared library at '/Library/Frameworks/R.framework/Resources/lib/libR.dylib' could not be opened: DlOpen { desc: "dlopen(/Library/Frameworks/R.framework/Resources/lib/libR.dylib, 0x0009): tried: '/Library/Frameworks/R.framework/Resources/lib/libR.dylib' (mach-o file, but is an incompatible architecture (have 'arm64', need 'x86_64')), '/Library/Frameworks/R.framework/Resources/lib/libR.dylib' (mach-o file, but is an incompatible architecture (have 'arm64', need 'x86_64')), '/System/Volumes/Preboot/Cryptexes/OS/Library/Frameworks/R.framework/Resources/lib/libR.dylib' (no such file), '/Library/Frameworks/R.framework/Resources/lib/libR.dylib' (mach-o file, but is an incompatible architecture (have 'arm64', need 'x86_64')), '/Library/Frameworks/R.framework/Resources/lib/libR.dylib' (mach-o file, but is an incompatible architecture (have 'arm64', need 'x86_64')), '/Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libR.dylib' (mach-o file, but is an incompatible architecture (have 'arm64', need 'x86_64')), '/System/Volumes/Preboot/Cryptexes/OS/Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libR.dylib' (no such file), '/Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libR.dylib' (mach-o file, but is an incompatible architecture (have 'arm64', need 'x86_64'))" }

output.log