diff --git a/.github/scripts/shorten-conda-env-windows.sh b/.github/scripts/shorten-conda-env-windows.sh
new file mode 100644
index 0000000000..0ff1d2d2d5
--- /dev/null
+++ b/.github/scripts/shorten-conda-env-windows.sh
@@ -0,0 +1,108 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+if [[ -z "${CONDA_ENV:-}" ]]; then
+  echo "::error::CONDA_ENV is not set"
+  exit 1
+fi
+
+if [[ -z "${GITHUB_ENV:-}" ]]; then
+  echo "::error::GITHUB_ENV is not set"
+  exit 1
+fi
+
+if ! command -v cygpath >/dev/null 2>&1; then
+  echo "::error::cygpath is required to shorten Windows paths"
+  exit 1
+fi
+
+to_windows_path() {
+  local path="${1//\\//}"
+
+  if [[ "${path}" =~ ^[A-Za-z]:/ ]]; then
+    printf "%s\n" "${path//\//\\}"
+  else
+    cygpath -w "${path}"
+  fi
+}
+
+to_bash_path() {
+  local path="${1//\\//}"
+
+  if [[ "${path}" =~ ^([A-Za-z]):(/.*)?$ ]]; then
+    printf "/%s%s\n" "${BASH_REMATCH[1],,}" "${BASH_REMATCH[2]}"
+  else
+    printf "%s\n" "${path}"
+  fi
+}
+
+find_unused_drive() {
+  local drive
+
+  for drive in T S R Q P O N M L K J I H G F E D; do
+    if [[ ! -e "/${drive,,}" ]]; then
+      printf "%s:\n" "${drive}"
+      return 0
+    fi
+  done
+
+  return 1
+}
+
+conda_env="${CONDA_ENV%/}"
+conda_env_bash="$(to_bash_path "${conda_env}")"
+conda_env_name="$(basename "${conda_env_bash}")"
+conda_env_parent="$(dirname "${conda_env_bash}")"
+conda_env_parent_win="$(to_windows_path "${conda_env_parent}")"
+
+if [[ -n "${SHORT_CONDA_DRIVE:-}" ]]; then
+  short_drive="${SHORT_CONDA_DRIVE%:}:"
+elif ! short_drive="$(find_unused_drive)"; then
+  echo "::error::Could not find an unused drive letter for the Conda env path"
+  exit 1
+fi
+
+if [[ ! "${short_drive}" =~ ^[A-Za-z]:$ ]]; then
+  echo "::error::SHORT_CONDA_DRIVE must be a Windows drive letter like T:"
+  exit 1
+fi
+
+MSYS2_ARG_CONV_EXCL="*" MSYS2_ENV_CONV_EXCL="CONDA_ENV_PARENT_WIN" SHORT_CONDA_DRIVE="${short_drive}" CONDA_ENV_PARENT_WIN="${conda_env_parent_win}" powershell.exe -NoProfile -ExecutionPolicy Bypass -Command '
+$ErrorActionPreference = "Stop"
+$drive = $env:SHORT_CONDA_DRIVE
+$target = $env:CONDA_ENV_PARENT_WIN
+$target = $target -replace "^[\\/]+(?=[A-Za-z]:[\\/])", ""
+Write-Host "Mapping Conda env parent path: $target"
+if (-not (Test-Path -LiteralPath $target -PathType Container)) {
+  throw "Conda env parent path not found: $target"
+}
+& subst.exe $drive /D 2>$null
+& subst.exe $drive $target
+if ($LASTEXITCODE -ne 0) {
+  throw "subst failed to map $drive to $target"
+}
+'
+
+short_conda_env="${short_drive}/${conda_env_name}"
+short_conda_run="conda run --no-capture-output -p ${short_conda_env}"
+
+{
+  echo "CONDA_ENV=${short_conda_env}"
+  echo "CONDA_RUN=${short_conda_run}"
+} >> "${GITHUB_ENV}"
+
+build_env_file="${BUILD_ENV_FILE:-}"
+if [[ -n "${build_env_file}" ]]; then
+  build_env_file="$(to_bash_path "${build_env_file}")"
+fi
+
+if [[ -n "${build_env_file}" && -f "${build_env_file}" ]]; then
+  {
+    printf "export CONDA_ENV=%q\n" "${short_conda_env}"
+    printf "export CONDA_RUN=%q\n" "${short_conda_run}"
+  } >> "${build_env_file}"
+fi
+
+echo "Mapped ${conda_env_parent_win} to ${short_drive}"
+echo "Using ${short_conda_env} as the Conda environment prefix"
diff --git a/.github/workflows/build-tensorrt-windows.yml b/.github/workflows/build-tensorrt-windows.yml
index b9be0b0530..3c69427a22 100644
--- a/.github/workflows/build-tensorrt-windows.yml
+++ b/.github/workflows/build-tensorrt-windows.yml
@@ -131,6 +131,9 @@ jobs:
           python-version: ${{ env.PYTHON_VERSION }}
           cuda-version: ${{ env.CU_VERSION }}
           arch: ${{ env.ARCH }}
+      - name: Shorten Conda environment path
+        run: |
+          bash "${REPOSITORY}/.github/scripts/shorten-conda-env-windows.sh"
       - name: Install XPU support package
         if: ${{ matrix.gpu_arch_type == 'xpu' }}
         run: |
diff --git a/.github/workflows/build_windows.yml b/.github/workflows/build_windows.yml
index ba5b6ac1a9..5187f6e2a6 100644
--- a/.github/workflows/build_windows.yml
+++ b/.github/workflows/build_windows.yml
@@ -167,6 +167,10 @@ jobs:
           python-version: ${{ env.PYTHON_VERSION }}
           cuda-version: ${{ env.CU_VERSION }}
           arch: ${{ inputs.architecture }}
+      - name: Shorten Conda environment path
+        if: inputs.architecture == 'x64'
+        run: |
+          bash "${REPOSITORY}/.github/scripts/shorten-conda-env-windows.sh"
       - name: Install XPU support package
         if: ${{ matrix.gpu_arch_type == 'xpu' }}
         env:
diff --git a/.github/workflows/windows-test.yml b/.github/workflows/windows-test.yml
index ad17387e7c..0d919ca3c3 100644
--- a/.github/workflows/windows-test.yml
+++ b/.github/workflows/windows-test.yml
@@ -102,6 +102,10 @@ jobs:
           python-version: ${{ env.PYTHON_VERSION }}
           cuda-version: ${{ env.CU_VERSION }}
           arch: ${{ env.ARCH }}
+      - name: Shorten Conda environment path
+        if: inputs.architecture == 'x64'
+        run: |
+          bash "${REPOSITORY}/.github/scripts/shorten-conda-env-windows.sh"
       - name: Run Pre-Script with Caching
         if: ${{ inputs.pre-script != '' }}
         uses: ./test-infra/.github/actions/run-script-with-cache
diff --git a/packaging/pre_build_script_windows.sh b/packaging/pre_build_script_windows.sh
index 0b52e24064..9698ba07ce 100644
--- a/packaging/pre_build_script_windows.sh
+++ b/packaging/pre_build_script_windows.sh
@@ -1,6 +1,6 @@
 set -x
 
-pip install -U numpy packaging pyyaml setuptools wheel fmt
+python -m pip install -U numpy packaging pyyaml setuptools wheel fmt
 
 choco install bazelisk -y
 
@@ -20,12 +20,13 @@ fi
 TORCH=$(grep "^torch>" py/requirements.txt)
 INDEX_URL=https://download.pytorch.org/whl/${CHANNEL}/${CU_VERSION}
 
-# Install all the dependencies required for Torch-TensorRT
-pip uninstall -y torch torchvision
-pip install --force-reinstall --pre ${TORCH} --index-url ${INDEX_URL}
+# The workflow installs torch before this script runs. Avoid uninstalling and
+# force-reinstalling it here: with the shortened Windows conda prefix, pip can
+# rediscover a half-removed torch dist-info through the original C:\ path.
+python -m pip install --pre "${TORCH}" --index-url "${INDEX_URL}" || exit 1
 
 export CUDA_HOME="$(echo ${CUDA_PATH} | sed -e 's#\\#\/#g')"
-export TORCH_INSTALL_PATH="$(python -c "import torch, os; print(os.path.dirname(torch.__file__))" | sed -e 's#\\#\/#g')"
+export TORCH_INSTALL_PATH="$(python -c "import torch, os; print(os.path.dirname(torch.__file__).replace('\\\\', '/'))")" || exit 1
 
 # tried with conda install -c conda-forge fmt -y, but build still failed in windows with the following error:
 # C:\actions-runner\_work\_temp\conda_environment_18042354682\lib\site-packages\torch\include\torch/csrc/utils/python_arg_parser.h(42): fatal error C1083: Cannot open include file: 'fmt/format.h': No such file or directory