diff --git a/src/Simplex/FileTransfer/Agent.hs b/src/Simplex/FileTransfer/Agent.hs
index 9a789a104..f45389462 100644
--- a/src/Simplex/FileTransfer/Agent.hs
+++ b/src/Simplex/FileTransfer/Agent.hs
@@ -393,7 +393,7 @@ runXFTPSndPrepareWorker c Worker {doWork} = do
           let CryptoFile {filePath} = srcFile
               fileName = takeFileName filePath
           fileSize <- liftIO $ fromInteger <$> CF.getFileContentsSize srcFile
-          when (fileSize > maxFileSize) $ throwError $ INTERNAL "max file size exceeded"
+          when (fileSize > maxFileSizeHard) $ throwError $ INTERNAL "max file size exceeded"
           let fileHdr = smpEncode FileHeader {fileName, fileExtra = Nothing}
               fileSize' = fromIntegral (B.length fileHdr) + fileSize
               chunkSizes = prepareChunkSizes $ fileSize' + fileSizeLen + authTagSize
diff --git a/src/Simplex/FileTransfer/Client/Main.hs b/src/Simplex/FileTransfer/Client/Main.hs
index e1ef9f0d8..c0277cd9f 100644
--- a/src/Simplex/FileTransfer/Client/Main.hs
+++ b/src/Simplex/FileTransfer/Client/Main.hs
@@ -19,6 +19,7 @@ module Simplex.FileTransfer.Client.Main
     prepareChunkSizes,
     prepareChunkSpecs,
     maxFileSize,
+    maxFileSizeHard,
     fileSizeLen,
     getChunkDigest,
     SentRecipientReplica (..),
@@ -76,12 +77,17 @@ import UnliftIO.Directory
 xftpClientVersion :: String
 xftpClientVersion = "1.0.1"
 
+-- | Soft limit for XFTP clients. Should be checked and reported to user.
 maxFileSize :: Int64
 maxFileSize = gb 1
 
 maxFileSizeStr :: String
 maxFileSizeStr = B.unpack . strEncode $ FileSize maxFileSize
 
+-- | Hard internal limit for XFTP agent after which it refuses to prepare chunks.
+maxFileSizeHard :: Int64
+maxFileSizeHard = gb 5
+
 fileSizeLen :: Int64
 fileSizeLen = 8