diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 118f48a702..8ece30c83b 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -16,11 +16,8 @@ jobs:
       fail-fast: false
       matrix:
         # macos-13 is x86; macos-14 is ARM
-        os: [ubuntu-latest, macos-13, macos-14, windows-latest]
+        os: [windows-latest]
         cargo_flags: [""]
-        include:
-        - os: ubuntu-latest
-          cargo_flags: "--all-features"
     runs-on: ${{ matrix.os }}
 
     # TODO FIXME (aseipp): keep the timeout limit to ~15 minutes. this is long
@@ -38,32 +35,6 @@ jobs:
     steps:
     - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
 
-    # The default version of gpg installed on the runners is a version baked in with git
-    # which only contains the components needed by git and doesn't work for our test cases. 
-    #
-    # This installs the latest gpg4win version, which is a variation of GnuPG built for
-    # Windows.
-    #
-    # There is some issue with windows PATH max length which is what all the PATH wrangling
-    # below is for. Please see the below link for where this fix was derived from:
-    # https://github.com/orgs/community/discussions/24933
-    - name: Setup GnuPG [windows]
-      if: ${{ matrix.os == 'windows-latest' }}
-      run: |
-        $env:PATH = "C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\ProgramData\chocolatey\bin"
-        [Environment]::SetEnvironmentVariable("Path", $env:PATH, "Machine")
-        choco install --yes gpg4win
-        echo "C:\Program Files (x86)\Gpg4win\..\GnuPG\bin" >> $env:GITHUB_PATH
-
-    # The default version of openssh on windows server is quite old (8.1) and doesn't have
-    # all the necessary signing/verification commands available (such as -Y find-principals)
-    - name: Setup ssh-agent [windows]
-      if: ${{ matrix.os == 'windows-latest' }}
-      run: |
-        Remove-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0
-        Remove-WindowsCapability -Online -Name OpenSSH.Client~~~~0.0.1.0
-        choco install openssh --pre
-
     - name: Install Rust
       uses: dtolnay/rust-toolchain@1482605bfc5719782e1267fd0c0cc350fe7646b8
       with:
@@ -71,7 +42,7 @@ jobs:
     - name: Build
       run: cargo build --workspace --all-targets --verbose ${{ matrix.cargo_flags }}
     - name: Test
-      run: cargo test --workspace --all-targets --verbose ${{ matrix.cargo_flags }}
+      run: cargo test working --workspace --all-targets --verbose ${{ matrix.cargo_flags }} --no-fail-fast -- --show-output
       env:
         RUST_BACKTRACE: 1
 
diff --git a/Cargo.lock b/Cargo.lock
index 7cba36cdfa..69bd34fef9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1890,6 +1890,7 @@ dependencies = [
  "config",
  "criterion",
  "digest",
+ "dunce",
  "either",
  "esl01-renderdag",
  "futures 0.3.31",
diff --git a/lib/Cargo.toml b/lib/Cargo.toml
index b75e3bf49b..07a6d3c783 100644
--- a/lib/Cargo.toml
+++ b/lib/Cargo.toml
@@ -42,6 +42,7 @@ chrono-english = { workspace = true }
 clru = { workspace = true }
 config = { workspace = true }
 digest = { workspace = true }
+dunce = { workspace = true }
 either = { workspace = true }
 futures = { workspace = true }
 git2 = { workspace = true, optional = true }
diff --git a/lib/tests/test_local_working_copy.rs b/lib/tests/test_local_working_copy.rs
index 8d328ea9e9..ccad43f53d 100644
--- a/lib/tests/test_local_working_copy.rs
+++ b/lib/tests/test_local_working_copy.rs
@@ -1329,7 +1329,7 @@ fn test_check_out_existing_file_symlink_icase_fs(victim_exists: bool) {
     if victim_exists {
         std::fs::write(&victim_file_path, "old").unwrap();
     }
-    assert_eq!(workspace_root.join("parent").exists(), victim_exists);
+    assert_eq!(workspace_root.join("parent").try_exists().unwrap(), victim_exists);
 
     let file_path = RepoPath::from_internal_string("PARENT");
     let tree = create_tree(repo, &[(file_path, "bad")]);
@@ -1348,7 +1348,7 @@ fn test_check_out_existing_file_symlink_icase_fs(victim_exists: bool) {
     if victim_exists {
         assert_eq!(std::fs::read(&victim_file_path).unwrap(), b"old");
     } else {
-        assert!(!victim_file_path.exists());
+        assert!(!victim_file_path.try_exists().unwrap());
     }
 }
 
@@ -1632,7 +1632,23 @@ fn test_check_out_reserved_file_path_vfat(vfat_path_str: &str, file_path_strs: &
     let repo = &test_workspace.repo;
     let workspace_root = test_workspace.workspace.workspace_root().to_owned();
     std::fs::create_dir(workspace_root.join(".git")).unwrap();
+    std::fs::create_dir(workspace_root.join("..git")).unwrap();
+    std::fs::create_dir(workspace_root.join("...git")).unwrap();
+    std::fs::create_dir(workspace_root.join("....git")).unwrap();
+    std::fs::create_dir(workspace_root.join(".....git")).unwrap();
+    assert!(workspace_root.join(".jj").exists());
     let is_vfat = check_vfat(&workspace_root);
+    for i in 0..=9 {
+        for name in ["GIT", "JJ"] {
+            let path = workspace_root.join(format!("{name}~{i}"));
+            eprintln!("XXX {} {}", path.display(), path.exists());
+        }
+    }
+    std::process::Command::new("cmd")
+        .args(["/c", "dir /x"])
+        .current_dir(dunce::simplified(&workspace_root))
+        .status()
+        .unwrap();
 
     let vfat_disk_path = workspace_root.join(vfat_path_str);
     let file_paths = file_path_strs