diff --git a/news/changelog-1.4.md b/news/changelog-1.4.md
index 6a107c16f9..67d065de3c 100644
--- a/news/changelog-1.4.md
+++ b/news/changelog-1.4.md
@@ -83,6 +83,7 @@
 - Exit if project pre or post render script fails
 - Use InternalError in typescript code, and offer a more helpful error message when an internal error happens.
 - ([#6042](https://github.com/quarto-dev/quarto-cli/issues/6042)): Correctly support empty lines in YAML blocks.
+- ([#6154](https://github.com/quarto-dev/quarto-cli/issues/6154)): `quarto check knitr` does not fail anymore when user's `.Rprofile` contains `cat()` calls.
 
 ## Docusaurus Format
 
diff --git a/src/core/knitr.ts b/src/core/knitr.ts
index 09080809ba..a96c444d46 100644
--- a/src/core/knitr.ts
+++ b/src/core/knitr.ts
@@ -1,9 +1,8 @@
 /*
-* knitr.ts
-*
-* Copyright (C) 2020-2022 Posit Software, PBC
-*
-*/
+ * knitr.ts
+ *
+ * Copyright (C) 2020-2022 Posit Software, PBC
+ */
 
 import * as colors from "fmt/colors.ts";
 
@@ -44,7 +43,11 @@ export async function knitrCapabilities() {
       stdout: "piped",
     });
     if (result.success && result.stdout) {
-      const caps = readYamlFromString(result.stdout) as KnitrCapabilities;
+      const jsonLines = result.stdout
+        .replace(/^.*--- YAML_START ---/sm, "")
+        .replace(/--- YAML_END ---.*$/sm, "");
+
+      const caps = readYamlFromString(jsonLines) as KnitrCapabilities;
       // check knitr requirement
       const knitrVersion = caps.packages.knitr
         ? coerce(caps.packages.knitr)
diff --git a/src/resources/capabilities/knitr.R b/src/resources/capabilities/knitr.R
index 253cd1d09b..89499aa533 100644
--- a/src/resources/capabilities/knitr.R
+++ b/src/resources/capabilities/knitr.R
@@ -1,4 +1,5 @@
 version <- getRversion()
+cat("--- YAML_START ---\n")
 cat("versionMajor:", version$major, "\n")
 cat("versionMinor:", version$minor, "\n")
 cat("versionPatch:", version$patch, "\n")
@@ -21,4 +22,5 @@ if (requireNamespace("rmarkdown", quietly = TRUE)) {
 } else {
   cat("null")
 }
-cat("\n")
\ No newline at end of file
+cat("\n")
+cat("--- YAML_END ---\n")
\ No newline at end of file