Unable to launch RStudio suddenly

RStudio IDE
,
1

Hi Posit community, can anyone help me here?
Long time RStudio user, suddenly I can't open it. Uninstalled and reinstalled R and RStudio, cleared environ and profile files out. Message below looks like I can't access the package manifest, but I can get the file through my web browser. Any thoughts? I wonder if Rstudio has some firewall rules applied that browser doesn't. Running on Windows (and had not problem in the past).

Thanks for any suggests, log summary below.

Chris

R Session Startup Failure Report

RStudio Version

RStudio 2026.04.0+526 "Globemaster Allium " (57f8932a, 2026-04-18) for windows

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) RStudio/2026.04.0+526 Chrome/142.0.7444.265 Electron/39.8.7 Safari/537.36

Error message

[No error available]

Process Output

The R session exited with code 3221225477.

Error output:

[No errors emitted]

Standard output:

[No output emitted]

Logs

C:/Users/ChrisMainey(Birmingh/AppData/Local/RStudio/log/rsession-ChrisMainey(Birmingh.log

2026-05-06T14:52:20.272245Z [rsession-ChrisMainey(Birmingh] WARNING [downloadManifest]: Failed to download manifest: Error in download.file(url = "https://cdn.posit.co/posit-ai/manifest.json",  : |||  cannot open URL 'https://cdn.posit.co/posit-ai/manifest.json'; LOGGED FROM: class rstudio::core::Error __cdecl rstudio::session::modules::chat::`anonymous-namespace'::downloadManifest(class rstudio::core::json::Object *) C:\Users\jenkins\workspace\ide-os-windows\rel-globemaster-allium\src\cpp\session\modules\SessionChat.cpp:3445
2026-05-06T14:52:20.289060Z [rsession-ChrisMainey(Birmingh] WARNING [checkForUpdatesOnStartup]: Failed to download manifest: Error in download.file(url = "https://cdn.posit.co/posit-ai/manifest.json",  : |||  cannot open URL 'https://cdn.posit.co/posit-ai/manifest.json'; LOGGED FROM: class rstudio::core::Error __cdecl rstudio::session::modules::chat::`anonymous-namespace'::checkForUpdatesOnStartup(void) C:\Users\jenkins\workspace\ide-os-windows\rel-globemaster-allium\src\cpp\session\modules\SessionChat.cpp:4087
2026-05-06T14:52:20.289060Z [rsession-ChrisMainey(Birmingh] WARNING [checkForUpdatesOnStartup]: Failed to download manifest: Error in download.file(url = "https://cdn.posit.co/posit-ai/manifest.json",  : |||  cannot open URL 'https://cdn.posit.co/posit-ai/manifest.json'; LOGGED FROM: class rstudio::core::Error __cdecl rstudio::session::modules::chat::`anonymous-namespace'::checkForUpdatesOnStartup(void) C:\Users\jenkins\workspace\ide-os-windows\rel-globemaster-allium\src\cpp\session\modules\SessionChat.cpp:4087
1 Like
2

I had the same issue and couldn't fix it. I went finaly to Positron however I preferred a lot more RStudio. Finaly I find Positron friendly and can do the same as in RStudio. Go to Positron and in a short time
you woll find it pleasant.

1 Like
3

Hi, that particular error shouldn't prevent RStudio from starting and being usable. The only feature impacted by it is the optional Posit Assistant feature. So if RStudio is failing to start altogether, this error is probably not the root cause.

You are getting the main RStudio window, but it just shows the error information you included in your initial post? The "R Session Startup Failure Report"?

Have you tried clearing state per https://support.posit.co/hc/en-us/articles/200534577-Resetting-RStudio-Desktop-s-State?

Regarding the manifest.json download error, if you can load that file via web browser, but RStudio cannot, then you are likely behind a proxy server. The download of this file is done by R's download.file() mechanism with libcurl under the covers, which unfortunately does not pick up the operating system proxy settings automatically. It must be configured separately. There are a bunch of details here: Proxies and Certificates on Windows Networks.

1 Like
4

We identified an issue where RStudio will hang at startup if not connected to the internet, when it tries to download the manifest.

Not what you are hitting since you said you can load the file via web browser, but for others who might be hitting this thought I'd mention it here.

Fix is in process, targeting the June release of RStudio.

1 Like
5

Hello,

Our rstudio server runs in a network not connected to internet
So we get

May 21 08:11:42 r-studio rsession-dep[1340]: WARNING [downloadManifest]: Failed to download manifest: Error in download.file(url = "https://cdn.posit.co/posit-ai/manifest.json", : ||| cannot open URL 'https://cdn.posit.co/posit-ai>
May 21 08:11:42 r-studio rsession-dep[1340]: WARNING [checkForUpdatesOnStartup]: Failed to download manifest: Error in download.file(url = "https://cdn.posit.co/posit-ai/manifest.json", : ||| cannot open URL 'https://cdn.posit.co/>

So it takes a while until R runs and we have the message:
"R is taking longer to start than usual"

Is it possible to disable those downloads ?

Thanks

1 Like
6

Yes, you can suppress this by setting the environment variable RSTUDIO_DISABLE_POSIT_ASSISTANT=1. This must be set before sessions are started.

With this set, the Posit Assistant features are entirely hidden and the attempt to fetch the manifest is prevented.

Sorry about this, we have a fix incoming to make it so this doesn't stall RStudio startup on machines not connected to the internet, will be in the June release (details here defer posit assistant manifest fetch off session init path by kevinushey · Pull Request #17686 · rstudio/rstudio · GitHub).

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