2 files changed, 5 insertions, 2 deletions

diff --git a/server/helpers/custom-validators/video-captions.ts b/server/helpers/custom-validators/video-captions.ts
index 6b1729f36..177e9e86e 100644
--- a/server/helpers/custom-validators/video-captions.ts
+++ b/server/helpers/custom-validators/video-captions.ts
@@ -8,7 +8,9 @@ function isVideoCaptionLanguageValid (value: any) {
   return exists(value) && VIDEO_LANGUAGES[ value ] !== undefined
 }
 
-const videoCaptionTypes = Object.keys(VIDEO_CAPTIONS_MIMETYPE_EXT).map(m => `(${m})`)
+const videoCaptionTypes = Object.keys(VIDEO_CAPTIONS_MIMETYPE_EXT)
+                                .concat([ 'application/octet-stream' ]) // MacOS sends application/octet-stream ><
+                                .map(m => `(${m})`)
 const videoCaptionTypesRegex = videoCaptionTypes.join('|')
 function isVideoCaptionFile (files: { [ fieldname: string ]: Express.Multer.File[] } | Express.Multer.File[], field: string) {
   return isFileValid(files, videoCaptionTypesRegex, field, CONSTRAINTS_FIELDS.VIDEO_CAPTIONS.CAPTION_FILE.FILE_SIZE.max)
diff --git a/server/helpers/express-utils.ts b/server/helpers/express-utils.ts
index f136a4329..b3cc40848 100644
--- a/server/helpers/express-utils.ts
+++ b/server/helpers/express-utils.ts
@@ -4,6 +4,7 @@ import { CONFIG, REMOTE_SCHEME } from '../initializers'
 import { logger } from './logger'
 import { User } from '../../shared/models/users'
 import { generateRandomString } from './utils'
+import { extname } from 'path'
 
 function buildNSFWFilter (res: express.Response, paramNSFW?: string) {
   if (paramNSFW === 'true') return true
@@ -50,7 +51,7 @@ function createReqFiles (
     },
 
     filename: async (req, file, cb) => {
-      const extension = mimeTypes[ file.mimetype ]
+      const extension = mimeTypes[ file.mimetype ] || extname(file.originalname)
       let randomString = ''
 
       try {