diff --git a/internal/buffer/buffer.go b/internal/buffer/buffer.go
index c1bf6f10..1d899663 100644
--- a/internal/buffer/buffer.go
+++ b/internal/buffer/buffer.go
@@ -64,10 +64,6 @@ var (
 	// BTStdout is a buffer that only writes to stdout
 	// when closed
 	BTStdout = BufType{6, false, true, true}
-
-	// ErrFileTooLarge is returned when the file is too large to hash
-	// (fastdirty is automatically enabled)
-	ErrFileTooLarge = errors.New("File is too large to hash")
 )
 
 // SharedBuffer is a struct containing info that is shared among buffers
@@ -649,32 +645,23 @@ func (b *Buffer) Size() int {
 }
 
 // calcHash calculates md5 hash of all lines in the buffer
-func calcHash(b *Buffer, out *[md5.Size]byte) error {
+func calcHash(b *Buffer, out *[md5.Size]byte) {
 	h := md5.New()
 
-	size := 0
 	if len(b.lines) > 0 {
-		n, _ := h.Write(b.lines[0].data)
-		size += n
+		h.Write(b.lines[0].data)
 
 		for _, l := range b.lines[1:] {
 			if b.Endings == FFDos {
-				n, _ = h.Write([]byte{'\r', '\n'})
+				h.Write([]byte{'\r', '\n'})
 			} else {
-				n, _ = h.Write([]byte{'\n'})
+				h.Write([]byte{'\n'})
 			}
-			size += n
-			n, _ = h.Write(l.data)
-			size += n
+			h.Write(l.data)
 		}
 	}
 
-	if size > LargeFileThreshold {
-		return ErrFileTooLarge
-	}
-
 	h.Sum((*out)[:0])
-	return nil
 }
 
 func parseDefFromFile(f config.RuntimeFile, header *highlight.Header) *highlight.Def {
diff --git a/internal/buffer/settings.go b/internal/buffer/settings.go
index e934da2f..9e76697c 100644
--- a/internal/buffer/settings.go
+++ b/internal/buffer/settings.go
@@ -12,15 +12,13 @@ func (b *Buffer) SetOptionNative(option string, nativeValue interface{}) error {
 
 	if option == "fastdirty" {
 		if !nativeValue.(bool) {
-			if !b.isModified {
-				e := calcHash(b, &b.origHash)
-				if e == ErrFileTooLarge {
-					b.Settings["fastdirty"] = true
-				}
+			if b.Size() > LargeFileThreshold {
+				b.Settings["fastdirty"] = true
 			} else {
-				b.origHash = [md5.Size]byte{}
-				if b.Size() > LargeFileThreshold {
-					b.Settings["fastdirty"] = true
+				if !b.isModified {
+					calcHash(b, &b.origHash)
+				} else {
+					b.origHash = [md5.Size]byte{}
 				}
 			}
 		}