diff --git a/ide/main.pp b/ide/main.pp
index 0307f7adce..ff2249d414 100644
--- a/ide/main.pp
+++ b/ide/main.pp
@@ -11471,14 +11471,23 @@ procedure TMainIDE.OnCodeBufferDecodeLoaded(Code: TCodeBuffer;
   const Filename: string; var Source, DiskEncoding, MemEncoding: string);
 begin
   //DebugLn(['TMainIDE.OnCodeBufferDecodeLoaded Filename=',Filename,' Encoding=',GuessEncoding(Source)]);
-  //DiskEncoding:=GuessEncoding(Source);
-  //MemEncoding:=EncodingUTF8;
+  DiskEncoding:=GuessEncoding(Source);
+  MemEncoding:=EncodingUTF8;
+  if (DiskEncoding<>MemEncoding) then begin
+    //DebugLn(['TMainIDE.OnCodeBufferDecodeLoaded Filename=',Filename,' Disk=',DiskEncoding,' to Mem=',MemEncoding]);
+    Source:=ConvertEncoding(Source,DiskEncoding,MemEncoding);
+    //DebugLn(['TMainIDE.OnCodeBufferDecodeLoaded ',Source]);
+  end;
 end;
 
 procedure TMainIDE.OnCodeBufferEncodeSaving(Code: TCodeBuffer;
   const Filename: string; var Source: string);
 begin
-
+  if (Code.DiskEncoding<>'') and (Code.MemEncoding<>'')
+  and (Code.DiskEncoding<>Code.MemEncoding) then begin
+    //DebugLn(['TMainIDE.OnCodeBufferEncodeSaving Filename=',Code.Filename,' Mem=',Code.MemEncoding,' to Disk=',Code.DiskEncoding]);
+    Source:=ConvertEncoding(Source,Code.MemEncoding,Code.DiskEncoding);
+  end;
 end;
 
 procedure TMainIDE.CodeToolBossPrepareTree(Sender: TObject);
diff --git a/lcl/lconvencoding.pas b/lcl/lconvencoding.pas
index bc0d19067e..10d2ad25d5 100644
--- a/lcl/lconvencoding.pas
+++ b/lcl/lconvencoding.pas
@@ -4013,21 +4013,28 @@ begin
   
   // use system encoding
   Result:=GetSystemEncoding;
+
+  if NormalizeEncoding(Result)=EncodingUTF8 then begin
+    // the system encoding is UTF-8, but it is not UTF-8
+    // use ISO-8859-1 instead. This encoding has a full 1:1 mapping to unicode,
+    // so no character is lost during conversions.
+    Result:='ISO-8859-1';
+  end;
 end;
 
 function ConvertEncoding(const s, FromEncoding, ToEncoding: string): string;
-// FromEncoding and ToEncoding must be normalized
 var
-  AFrom, ATo: String;
+  AFrom, ATo, SysEnc: String;
   {$ifdef Unix}
   SL: TStringList;
   FN1, FN2: String;
   {$endif}
 begin
-  AFrom:=FromEncoding;
-  ATo:=ToEncoding;
-  if AFrom=GetSystemEncoding then AFrom:=EncodingAnsi;
-  if ATo=GetSystemEncoding then ATo:=EncodingAnsi;
+  AFrom:=NormalizeEncoding(FromEncoding);
+  ATo:=NormalizeEncoding(ToEncoding);
+  SysEnc:=NormalizeEncoding(GetSystemEncoding);
+  if AFrom=EncodingAnsi then AFrom:=SysEnc;
+  if ATo=EncodingAnsi then ATo:=SysEnc;
   if AFrom=ATo then begin
     Result:=s;
     exit;
@@ -4035,19 +4042,19 @@ begin
   //DebugLn(['ConvertEncoding ',AFrom,' ',ATo]);
   
   if (AFrom=EncodingUTF8) then begin
-    if AFrom='iso88591' then begin Result:=UTF8ToISO_8859_1(s); exit; end;
-    if AFrom='cp1250' then begin Result:=UTF8ToCP1250(s); exit; end;
-    if AFrom='cp1251' then begin Result:=UTF8ToCP1251(s); exit; end;
-    if AFrom='cp1252' then begin Result:=UTF8ToCP1252(s); exit; end;
-    if AFrom='cp1253' then begin Result:=UTF8ToCP1253(s); exit; end;
-    if AFrom='cp1254' then begin Result:=UTF8ToCP1254(s); exit; end;
-    if AFrom='cp1255' then begin Result:=UTF8ToCP1255(s); exit; end;
-    if AFrom='cp1256' then begin Result:=UTF8ToCP1256(s); exit; end;
-    if AFrom='cp1257' then begin Result:=UTF8ToCP1257(s); exit; end;
-    if AFrom='cp1258' then begin Result:=UTF8ToCP1258(s); exit; end;
-    if AFrom='cp874' then begin  Result:=UTF8ToCP874(s);  exit; end;
+    if ATo='iso88591' then begin Result:=UTF8ToISO_8859_1(s); exit; end;
+    if ATo='cp1250' then begin Result:=UTF8ToCP1250(s); exit; end;
+    if ATo='cp1251' then begin Result:=UTF8ToCP1251(s); exit; end;
+    if ATo='cp1252' then begin Result:=UTF8ToCP1252(s); exit; end;
+    if ATo='cp1253' then begin Result:=UTF8ToCP1253(s); exit; end;
+    if ATo='cp1254' then begin Result:=UTF8ToCP1254(s); exit; end;
+    if ATo='cp1255' then begin Result:=UTF8ToCP1255(s); exit; end;
+    if ATo='cp1256' then begin Result:=UTF8ToCP1256(s); exit; end;
+    if ATo='cp1257' then begin Result:=UTF8ToCP1257(s); exit; end;
+    if ATo='cp1258' then begin Result:=UTF8ToCP1258(s); exit; end;
+    if ATo='cp874' then begin  Result:=UTF8ToCP874(s);  exit; end;
 
-    if (ATo=EncodingAnsi) and Assigned(ConvertUTF8ToAnsi) then begin
+    if (ATo=SysEnc) and Assigned(ConvertUTF8ToAnsi) then begin
       Result:=ConvertUTF8ToAnsi(s);
       exit;
     end;
@@ -4064,7 +4071,7 @@ begin
     if AFrom='cp1258' then begin Result:=CP1258ToUTF8(s); exit; end;
     if AFrom='cp874' then begin  Result:=CP874ToUTF8(s);  exit; end;
 
-    if (AFrom=EncodingAnsi) and Assigned(ConvertAnsiToUTF8) then begin
+    if (AFrom=SysEnc) and Assigned(ConvertAnsiToUTF8) then begin
       Result:=ConvertAnsiToUTF8(s);
       exit;
     end;