diff --git a/src/tools/miri/miri-script/Cargo.lock b/src/tools/miri/miri-script/Cargo.lock
index 0e11f6efd100..a049bfcbccd6 100644
--- a/src/tools/miri/miri-script/Cargo.lock
+++ b/src/tools/miri/miri-script/Cargo.lock
@@ -149,12 +149,6 @@ version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
 
-[[package]]
-name = "env_home"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c7f84e12ccf0a7ddc17a6c41c93326024c42920d7ee630d04950e6926645c0fe"
-
 [[package]]
 name = "errno"
 version = "0.3.13"
@@ -266,7 +260,6 @@ dependencies = [
  "shell-words",
  "tempfile",
  "walkdir",
- "which",
  "xshell",
 ]
 
@@ -497,18 +490,6 @@ dependencies = [
  "wit-bindgen-rt",
 ]
 
-[[package]]
-name = "which"
-version = "7.0.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "24d643ce3fd3e5b54854602a080f34fb10ab75e0b813ee32d00ca2b44fa74762"
-dependencies = [
- "either",
- "env_home",
- "rustix",
- "winsafe",
-]
-
 [[package]]
 name = "winapi-util"
 version = "0.1.9"
@@ -664,12 +645,6 @@ version = "0.53.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "271414315aff87387382ec3d271b52d7ae78726f5d44ac98b4f4030c91880486"
 
-[[package]]
-name = "winsafe"
-version = "0.0.19"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d135d17ab770252ad95e9a872d365cf3090e3be864a34ab46f48555993efc904"
-
 [[package]]
 name = "wit-bindgen-rt"
 version = "0.39.0"
diff --git a/src/tools/miri/miri-script/Cargo.toml b/src/tools/miri/miri-script/Cargo.toml
index 9240788d6bce..b3f82cd1d504 100644
--- a/src/tools/miri/miri-script/Cargo.toml
+++ b/src/tools/miri/miri-script/Cargo.toml
@@ -14,7 +14,6 @@ rust-version = "1.85"
 # This is needed to make this package build on stable when the parent package uses unstable cargo features.
 
 [dependencies]
-which = "7"
 walkdir = "2.3"
 itertools = "0.14"
 path_macro = "1.0"
diff --git a/src/tools/miri/miri-script/src/commands.rs b/src/tools/miri/miri-script/src/commands.rs
index e6ebdf54e385..9aaad9ca04a9 100644
--- a/src/tools/miri/miri-script/src/commands.rs
+++ b/src/tools/miri/miri-script/src/commands.rs
@@ -198,9 +198,6 @@ impl Command {
     }
 
     fn toolchain(flags: Vec<String>) -> Result<()> {
-        // Make sure rustup-toolchain-install-master is installed.
-        which::which("rustup-toolchain-install-master")
-            .context("Please install rustup-toolchain-install-master by running 'cargo install rustup-toolchain-install-master'")?;
         let sh = Shell::new()?;
         sh.change_dir(miri_dir()?);
         let new_commit = sh.read_file("rust-version")?.trim().to_owned();
@@ -227,7 +224,9 @@ impl Command {
         // Install and setup new toolchain.
         cmd!(sh, "rustup toolchain uninstall miri").run()?;
 
-        cmd!(sh, "rustup-toolchain-install-master -n miri -c cargo -c rust-src -c rustc-dev -c llvm-tools -c rustfmt -c clippy {flags...} -- {new_commit}").run()?;
+        cmd!(sh, "rustup-toolchain-install-master -n miri -c cargo -c rust-src -c rustc-dev -c llvm-tools -c rustfmt -c clippy {flags...} -- {new_commit}")
+            .run()
+            .context("Failed to run rustup-toolchain-install-master. If it is not installed, run 'cargo install rustup-toolchain-install-master'.")?;
         cmd!(sh, "rustup override set miri").run()?;
         // Cleanup.
         cmd!(sh, "cargo clean").run()?;