diff --git a/src/components/FilesUploader/FilesUploader.tsx b/src/components/FilesUploader/FilesUploader.tsx
index 2cc4ed2..5069c1c 100644
--- a/src/components/FilesUploader/FilesUploader.tsx
+++ b/src/components/FilesUploader/FilesUploader.tsx
@@ -1,4 +1,4 @@
-import React, { useState } from 'react';
+import React from 'react';
 import * as helpres from '@educt/helpers';
 import { Stack, Flex, Box, Icon, Text, Input, IconButton, Button } from '@chakra-ui/react';
 import { MdOutlineFilePresent } from 'react-icons/md';
@@ -12,12 +12,11 @@ import { FileSupportedFormatsEnum } from '@educt/enums';
 
 type FilesUploaderPropsType = {
   onChange: (files: File[]) => void;
-  files?: Array<File> | undefined;
+  files?: File[] | undefined;
 };
 
 const FilesUploader: React.FC<FilesUploaderPropsType> = ({ onChange, files }) => {
   const fileInputRef = useRef<HTMLInputElement>(null);
-  const [selectedFiles, setSelectedFiles] = useState<Array<File>>([]);
 
   const onSelectFileHandler = () => {
     if (fileInputRef.current) {
@@ -28,12 +27,9 @@ const FilesUploader: React.FC<FilesUploaderPropsType> = ({ onChange, files }) =>
   /**
    * Detach file
    */
-  const onRemoveSelectedFileHandler = (selectedFile: File) => () =>
-    setSelectedFiles(selectedFiles => {
-      const updated = selectedFiles.filter(file => file.name !== selectedFile.name);
-      onChange(updated);
-      return updated;
-    });
+  const onRemoveSelectedFileHandler = (selectedFile: File) => () => {
+    onChange([...Array.from(files?.filter(file => file.name !== selectedFile.name) || [])]);
+  };
 
   /**
    * Attach file
@@ -41,20 +37,13 @@ const FilesUploader: React.FC<FilesUploaderPropsType> = ({ onChange, files }) =>
   const onChangeFileHandler = (e: React.ChangeEvent<HTMLInputElement>) => {
     e.preventDefault();
 
-    const { files } = e.target;
-
-    if (files && files.length !== 0) {
-      const isAlreadySelected = selectedFiles.find(selectedFile =>
-        Array.from(files).some(file => file.name === selectedFile.name)
+    if (e.target.files && e.target.files.length !== 0) {
+      const isAlreadySelected = (files || []).find(selectedFile =>
+        Array.from(e.target.files || []).some(file => file.name === selectedFile.name)
       );
 
       if (isAlreadySelected) return;
-
-      setSelectedFiles(selectedFiles => {
-        const updated = [...selectedFiles, ...Array.from(files)];
-        onChange(updated);
-        return updated;
-      });
+      onChange([...Array.from(files || []), ...e.target.files]);
     }
   };
 
@@ -72,7 +61,7 @@ const FilesUploader: React.FC<FilesUploaderPropsType> = ({ onChange, files }) =>
       />
       {files && (
         <Stack>
-          {selectedFiles.map((file, index) => (
+          {files.map((file, index) => (
             <Flex
               key={index}
               alignItems={'center'}
diff --git a/src/components/Forms/LessonForm/LessonForm.tsx b/src/components/Forms/LessonForm/LessonForm.tsx
index 0d758f3..04ff826 100644
--- a/src/components/Forms/LessonForm/LessonForm.tsx
+++ b/src/components/Forms/LessonForm/LessonForm.tsx
@@ -37,7 +37,6 @@ const LessonForm: React.FC<LessonFormPropsType> = ({ onSubmit, buttonLabel, isLo
   const {
     control,
     register,
-    watch,
     formState: { errors, isDirty },
   } = reactHookForm;
 
@@ -104,7 +103,7 @@ const LessonForm: React.FC<LessonFormPropsType> = ({ onSubmit, buttonLabel, isLo
             )}
           />
           <Text as='small' color='red.500'>
-            {errors.materials?.map(m => m.message)}
+            {errors.materials?.message}
           </Text>
           <FormHelperText>
             Supported formats:{' '}
diff --git a/src/components/Forms/LessonForm/LessonForm.validator.ts b/src/components/Forms/LessonForm/LessonForm.validator.ts
index 210d574..b901a56 100644
--- a/src/components/Forms/LessonForm/LessonForm.validator.ts
+++ b/src/components/Forms/LessonForm/LessonForm.validator.ts
@@ -1,8 +1,8 @@
-import { VideoSupportedFormatsEnum } from '@educt/enums';
+import * as helpers from '@educt/helpers';
 import yup from '@educt/schema';
 
 const VIDEO_FILE_SIZE = 5000 * 1024 * 1024;
-const MATERIAL_FILE_SIZE = 10000 * 1024;
+const MATERIAL_FILE_SIZE = 100000 * 1024;
 
 const LessonFormSchema = yup.object().shape({
   title: yup.string().required('Title field name is required').max(90, 'Title must be at most 90 characters'),
@@ -13,25 +13,26 @@ const LessonFormSchema = yup.object().shape({
   duration: yup.string().required('Duration field name is required'),
   video: yup
     .mixed()
-    .test('fileSize', 'File size is too large', (value: File) => {
-      if (!value) return true;
-      return value && value.size <= VIDEO_FILE_SIZE;
-    })
-    .test('fileFormat', 'This file format is not supported', (value: File) => {
-      if (!value) return true;
-      return value && Object.values(VideoSupportedFormatsEnum).includes(value.type as VideoSupportedFormatsEnum);
-    })
+    .test(
+      'fileSize',
+      `File size is too large, maximum size is ${helpers.transformBytes(VIDEO_FILE_SIZE)}`,
+      (value: File) => {
+        if (!value) return true;
+        return value && value.size <= VIDEO_FILE_SIZE;
+      }
+    )
     .required('Video field name is required'),
-  // materials: yup
-  //   .mixed()
-  //   .test('fileSize', 'File size is too large', (value: File) => {
-  //     if (!value) return true;
-  //     return value && value.size <= VIDEO_FILE_SIZE;
-  //   })
-  //   .test('fileFormat', 'This file format is not supported', (value: File) => {
-  //     if (!value) return true;
-  //     return value && VIDEO_SUPPORTED_FORMATS.includes(value.type);
-  //   }),
+  materials: yup
+    .mixed()
+    .test(
+      'fileSize',
+      `File size is too large, maximum size is ${helpers.transformBytes(MATERIAL_FILE_SIZE)}`,
+      (values: File[]) => {
+        if (!values) return true;
+        return values && values.every(value => value.size <= MATERIAL_FILE_SIZE);
+      }
+    )
+    .optional(),
 });
 
 export default LessonFormSchema;
diff --git a/src/enums/index.ts b/src/enums/index.ts
index 5efc3ef..429a7e7 100644
--- a/src/enums/index.ts
+++ b/src/enums/index.ts
@@ -19,7 +19,7 @@ export enum VideoSupportedFormatsEnum {
 
 export enum FileSupportedFormatsEnum {
   PDF = 'application/pdf',
-  ZIP = 'application/zip',
+  ZIP = 'application/x-zip-compressed',
   RAR = 'application/x-rar-compressed',
   DOC = 'application/msword',
   DOCX = 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',