diff --git a/packages/bruno-app/src/components/RequestPane/FileBody/index.js b/packages/bruno-app/src/components/RequestPane/FileBody/index.js
index 6929799f0b8..3c99ad7b928 100644
--- a/packages/bruno-app/src/components/RequestPane/FileBody/index.js
+++ b/packages/bruno-app/src/components/RequestPane/FileBody/index.js
@@ -9,6 +9,7 @@ import StyledWrapper from './StyledWrapper';
 import FilePickerEditor from 'components/FilePickerEditor/index';
 import SingleLineEditor from 'components/SingleLineEditor/index';
 import MultiLineEditor from 'components/MultiLineEditor';
+import { normalizePath } from 'utils/common/path';
 
 const FileBody = ({ item, collection }) => {
   const dispatch = useDispatch();
@@ -31,7 +32,7 @@ const FileBody = ({ item, collection }) => {
     const param = cloneDeep(_param);
     switch (type) {
       case 'filePath': {
-        param.filePath = e.target.filePath;
+        param.filePath = normalizePath(e.target.filePath);
         param.contentType = '';
         break;
       }
diff --git a/packages/bruno-app/src/components/RequestPane/MultipartFormParams/index.js b/packages/bruno-app/src/components/RequestPane/MultipartFormParams/index.js
index 0f7cd4d3596..24cc9049023 100644
--- a/packages/bruno-app/src/components/RequestPane/MultipartFormParams/index.js
+++ b/packages/bruno-app/src/components/RequestPane/MultipartFormParams/index.js
@@ -68,7 +68,7 @@ const MultipartFormParams = ({ item, collection }) => {
         if (!Array.isArray(filePaths) || filePaths.length === 0) return;
 
         const processedPaths = filePaths.map((filePath) => {
-          return getRelativePathWithinBasePath(collection.pathname, filePath);
+          return getRelativePathWithinBasePath(collection.pathname, filePath, true);
         });
 
         const currentParams = item.draft
diff --git a/packages/bruno-cli/src/runner/prepare-request.js b/packages/bruno-cli/src/runner/prepare-request.js
index 78d4c89f6d3..faf411d42ac 100644
--- a/packages/bruno-cli/src/runner/prepare-request.js
+++ b/packages/bruno-cli/src/runner/prepare-request.js
@@ -406,6 +406,11 @@ const prepareRequest = async (item = {}, collection = {}) => {
       axiosRequest.headers['content-type'] = contentType;
 
       if (filePath) {
+        // Normalize Windows separators when running on POSIX, without breaking UNC paths on Windows
+        if (path.sep === '/') {
+          filePath = filePath.replace(/\\/g, '/');
+        }
+        filePath = path.normalize(filePath);
         if (!path.isAbsolute(filePath)) {
           filePath = path.join(collectionPath, filePath);
         }
diff --git a/packages/bruno-cli/src/utils/form-data.js b/packages/bruno-cli/src/utils/form-data.js
index 9bff10442a2..900ec76e616 100644
--- a/packages/bruno-cli/src/utils/form-data.js
+++ b/packages/bruno-cli/src/utils/form-data.js
@@ -26,6 +26,11 @@ const createFormData = (data, collectionPath) => {
       const filePaths = value || [];
       filePaths.forEach((filePath) => {
         let trimmedFilePath = filePath.trim();
+        // Normalize Windows separators when running on POSIX, without breaking UNC paths on Windows
+        if (path.sep === '/') {
+          trimmedFilePath = trimmedFilePath.replace(/\\/g, '/');
+        }
+        trimmedFilePath = path.normalize(trimmedFilePath);
         if (!path.isAbsolute(trimmedFilePath)) {
           trimmedFilePath = path.join(collectionPath, trimmedFilePath);
         }