diff --git a/.changeset/tall-ligers-rhyme.md b/.changeset/tall-ligers-rhyme.md
new file mode 100644
index 000000000..d23488037
--- /dev/null
+++ b/.changeset/tall-ligers-rhyme.md
@@ -0,0 +1,5 @@
+---
+'providence-analytics': patch
+---
+
+support fullPath notation in optimisedGlob
diff --git a/packages-node/providence-analytics/src/program/utils/optimised-glob.js b/packages-node/providence-analytics/src/program/utils/optimised-glob.js
index 60dd3f8d2..0d27cebca 100644
--- a/packages-node/providence-analytics/src/program/utils/optimised-glob.js
+++ b/packages-node/providence-analytics/src/program/utils/optimised-glob.js
@@ -130,6 +130,14 @@ function toUniqueArray(arr) {
   return Array.from(new Set(arr));
 }
 
+/**
+ * @param {string} glob
+ * @returns {boolean}
+ */
+function isRootGlob(glob) {
+  return glob.startsWith('/') || glob.startsWith('!/') || Boolean(glob.match(/^([A-Z]:\\|\\\\)/));
+}
+
 /**
  * @param {DirentWithPath} dirent
  * @param {{cwd:string}} cfg
@@ -162,7 +170,10 @@ function postprocessOptions(matchedEntries, options) {
   }
 
   if (options.absolute) {
-    filteredPaths = filteredPaths.map(f => toPosixPath(path.join(options.cwd, f)));
+    filteredPaths = filteredPaths.map(f => {
+      const isRootPath = isRootGlob(f);
+      return isRootPath ? toPosixPath(f) : toPosixPath(path.join(options.cwd, f));
+    });
     if (process.platform === 'win32') {
       const driveChar = path.win32.resolve(options.cwd).slice(0, 1).toUpperCase();
       filteredPaths = filteredPaths.map(f => `${driveChar}:${f}`);
@@ -183,19 +194,17 @@ function postprocessOptions(matchedEntries, options) {
 const getStartPath = memoize(
   /**
    * @param {string} glob
+   * @returns {string}
    */
   glob => {
     const reservedChars = ['?', '[', ']', '{', '}', ',', '.', '*'];
-    let hasFoundReservedChar = false;
-    return glob
-      .split('/')
-      .map(part => {
-        if (hasFoundReservedChar) return undefined;
-        hasFoundReservedChar = reservedChars.some(reservedChar => part.includes(reservedChar));
-        return hasFoundReservedChar ? undefined : part;
-      })
-      .filter(Boolean)
-      .join('/');
+    const startPathParts = [];
+    for (const part of glob.split('/')) {
+      const hasReservedChar = reservedChars.some(reservedChar => part.includes(reservedChar));
+      if (hasReservedChar) break;
+      startPathParts.push(part);
+    }
+    return startPathParts.join('/');
   },
 );
 
@@ -315,9 +324,12 @@ export async function optimisedGlob(globOrGlobs, providedOptions = {}) {
   const ignoreGlobs = options.ignore.map((/** @type {string} */ g) =>
     g.startsWith('!') ? g : `!${g}`,
   );
+  const globs = toUniqueArray([...regularGlobs, ...ignoreGlobs]);
 
   const optionsNotSupportedByNativeGlob = ['onlyDirectories', 'dot'];
-  const doesConfigAllowNative = !optionsNotSupportedByNativeGlob.some(opt => options[opt]);
+  const hasGlobWithFullPath = globs.some(isRootGlob);
+  const doesConfigAllowNative =
+    !optionsNotSupportedByNativeGlob.some(opt => options[opt]) && !hasGlobWithFullPath;
   if (isExperimentalFsGlobEnabled && options.fs.promises.glob && doesConfigAllowNative) {
     const negativeGlobs = [...ignoreGlobs, ...regularGlobs.filter(r => r.startsWith('!'))].map(r =>
       r.slice(1),
@@ -350,8 +362,6 @@ export async function optimisedGlob(globOrGlobs, providedOptions = {}) {
     );
   }
 
-  const globs = toUniqueArray([...regularGlobs, ...ignoreGlobs]);
-
   /** @type {RegExp[]} */
   const matchRegexesNegative = [];
   /** @type {RegExp[]} */
@@ -377,11 +387,13 @@ export async function optimisedGlob(globOrGlobs, providedOptions = {}) {
 
     // Search for the "deepest" starting point in the filesystem that we can use to search the fs
     const startPath = getStartPath(globNormalized);
-    const fullStartPath = path.join(options.cwd, startPath);
+    const isRootPath = isRootGlob(startPath);
+    const cwd = isRootPath ? '/' : options.cwd;
+    const fullStartPath = path.join(cwd, startPath);
 
     try {
       const allDirEntsRelativeToCwd = await getAllDirentsRelativeToCwd(fullStartPath, {
-        cwd: options.cwd,
+        cwd,
         fs: options.fs,
       });
 
diff --git a/packages-node/providence-analytics/test-node/program/utils/optimised-glob.test.js b/packages-node/providence-analytics/test-node/program/utils/optimised-glob.test.js
index f0bcb2917..7b7e02edf 100644
--- a/packages-node/providence-analytics/test-node/program/utils/optimised-glob.test.js
+++ b/packages-node/providence-analytics/test-node/program/utils/optimised-glob.test.js
@@ -40,6 +40,8 @@ async function runOptimisedGlobAndCheckGlobbyParity(patterns, options) {
     );
   }
 
+  console.debug({ optimisedGlobResult, globbyResult });
+
   expect(optimisedGlobResult).to.deep.equal(globbyResult);
 
   return optimisedGlobResult;
@@ -302,6 +304,38 @@ function runSuiteForOptimisedGlob() {
         ).to.throw();
       });
     });
+
+    describe('Edge cases', () => {
+      it('allows prefixing a system path (regardless of cwd)', async () => {
+        const files = await runOptimisedGlobAndCheckGlobbyParity(
+          '/fakeFs/my/folder/*/some/file.{js,d.ts}',
+          testCfg,
+        );
+        expect(files).to.deep.equal([
+          '/fakeFs/my/folder/lvl1/some/file.d.ts',
+          '/fakeFs/my/folder/lvl1/some/file.js',
+        ]);
+        // With non-existing cwd
+        const files2 = await runOptimisedGlobAndCheckGlobbyParity(
+          '/fakeFs/my/folder/*/some/file.{js,d.ts}',
+          {
+            ...testCfg,
+            cwd: '/nonExisting/path', // this will not exist
+          },
+        );
+        expect(files2).to.deep.equal([
+          '/fakeFs/my/folder/lvl1/some/file.d.ts',
+          '/fakeFs/my/folder/lvl1/some/file.js',
+        ]);
+
+        // // With negative globs: this is not supported by globby
+        // const files3 = await runOptimisedGlobAndCheckGlobbyParity(
+        //   ['!/fakeFs/my/**/*.d.ts', '/fakeFs/my/folder/*/some/file.{js,d.ts}'],
+        //   testCfg,
+        // );
+        // expect(files3).to.deep.equal(['/fakeFs/my/folder/lvl1/some/file.js']);
+      });
+    });
   });
 }