diff --git a/backend/onedrive/onedrive.go b/backend/onedrive/onedrive.go
index 4afdab76c..93fa73db1 100644
--- a/backend/onedrive/onedrive.go
+++ b/backend/onedrive/onedrive.go
@@ -226,8 +226,9 @@ func init() {
 			Name: "chunk_size",
 			Help: `Chunk size to upload files with - must be multiple of 320k (327,680 bytes).
 
-Above this size files will be chunked - must be multiple of 320k (327,680 bytes). Note
-that the chunks will be buffered into memory.`,
+Above this size files will be chunked - must be multiple of 320k (327,680 bytes) and
+should not exceed 250M (262,144,000 bytes) else you may encounter \"Microsoft.SharePoint.Client.InvalidClientQueryException: The request message is too big.\"
+Note that the chunks will be buffered into memory.`,
 			Default:  defaultChunkSize,
 			Advanced: true,
 		}, {