Index: generic/tclUtil.c
==================================================================
--- generic/tclUtil.c
+++ generic/tclUtil.c
@@ -4210,10 +4210,11 @@
 {
     const char *bytes;
     Tcl_HashTable *cacheMap;
     Tcl_HashEntry *hPtr;
     int dummy;
+    Tcl_DString ds;
 
     Tcl_MutexLock(&pgvPtr->mutex);
 
     /*
      * Fill the global string value.
@@ -4224,12 +4225,15 @@
 	ckfree(pgvPtr->value);
     } else {
 	Tcl_CreateExitHandler(FreeProcessGlobalValue, pgvPtr);
     }
     bytes = TclGetStringFromObj(newValue, &pgvPtr->numBytes);
+    Tcl_UtfToExternalDString(encoding, bytes, pgvPtr->numBytes, &ds);
+    pgvPtr->numBytes = Tcl_DStringLength(&ds);
     pgvPtr->value = (char *)ckalloc(pgvPtr->numBytes + 1);
-    memcpy(pgvPtr->value, bytes, pgvPtr->numBytes + 1);
+    memcpy(pgvPtr->value, Tcl_DStringValue(&ds), pgvPtr->numBytes + 1);
+    Tcl_DStringFree(&ds);
     if (pgvPtr->encoding) {
 	Tcl_FreeEncoding(pgvPtr->encoding);
     }
     pgvPtr->encoding = encoding;
 
@@ -4267,10 +4271,11 @@
 {
     Tcl_Obj *value = NULL;
     Tcl_HashTable *cacheMap;
     Tcl_HashEntry *hPtr;
     int epoch = pgvPtr->epoch;
+    Tcl_DString newValue;
 
     if (pgvPtr->encoding) {
 	Tcl_Encoding current = Tcl_GetEncoding(NULL, NULL);
 
 	if (pgvPtr->encoding != current) {
@@ -4278,11 +4283,11 @@
 	     * The system encoding has changed since the global string value
 	     * was saved. Convert the global value to be based on the new
 	     * system encoding.
 	     */
 
-	    Tcl_DString native, newValue;
+	    Tcl_DString native;
 
 	    Tcl_MutexLock(&pgvPtr->mutex);
 	    epoch = ++pgvPtr->epoch;
 	    Tcl_UtfToExternalDString(pgvPtr->encoding, pgvPtr->value,
 		    pgvPtr->numBytes, &native);
@@ -4328,14 +4333,17 @@
 	    }
 	    Tcl_CreateExitHandler(FreeProcessGlobalValue, pgvPtr);
 	}
 
 	/*
-	 * Store a copy of the shared value in our epoch-indexed cache.
+	 * Store a copy of the shared value (but then in utf-8)
+	 * in our epoch-indexed cache.
 	 */
 
-	value = Tcl_NewStringObj(pgvPtr->value, pgvPtr->numBytes);
+	Tcl_ExternalToUtfDString(NULL, pgvPtr->value, pgvPtr->numBytes, &newValue);
+	value = Tcl_NewStringObj(Tcl_DStringValue(&newValue), Tcl_DStringLength(&newValue));
+	Tcl_DStringFree(&newValue);
 	hPtr = Tcl_CreateHashEntry(cacheMap,
 		INT2PTR(pgvPtr->epoch), &dummy);
 	Tcl_MutexUnlock(&pgvPtr->mutex);
 	Tcl_SetHashValue(hPtr, value);
 	Tcl_IncrRefCount(value);

Index: win/tclWinSock.c
==================================================================
--- win/tclWinSock.c
+++ win/tclWinSock.c
@@ -365,37 +365,34 @@
     DWORD length = sizeof(wbuf)/sizeof(WCHAR);
     Tcl_DString ds;
 
     if (GetComputerNameExW(ComputerNamePhysicalDnsFullyQualified, wbuf, &length) != 0) {
 	/*
-	 * Convert string from native to UTF then change to lowercase.
+	 * Convert string from WCHAR to utf-8, then change to lowercase,
+	 * then to system encoding.
 	 */
+	Tcl_DString inDs;
 
-	Tcl_UtfToLower(Tcl_WinTCharToUtf((TCHAR *)wbuf, -1, &ds));
-
+	Tcl_UtfToLower(Tcl_WinTCharToUtf((TCHAR *)wbuf, -1, &inDs));
+	Tcl_UtfToExternalDString(NULL, Tcl_DStringValue(&inDs), -1, &ds);
+	Tcl_DStringFree(&inDs);
     } else {
 	Tcl_DStringInit(&ds);
 	if (TclpHasSockets(NULL) == TCL_OK) {
 	    /*
 	     * The buffer size of 256 is recommended by the MSDN page that
 	     * documents gethostname() as being always adequate.
 	     */
 
-	    Tcl_DString inDs;
-
-	    Tcl_DStringInit(&inDs);
-	    Tcl_DStringSetLength(&inDs, 256);
-	    if (gethostname(Tcl_DStringValue(&inDs),
-		    Tcl_DStringLength(&inDs)) == 0) {
-		Tcl_ExternalToUtfDString(NULL, Tcl_DStringValue(&inDs),
-			-1, &ds);
-	    }
-	    Tcl_DStringFree(&inDs);
+	    Tcl_DStringInit(&ds);
+	    Tcl_DStringSetLength(&ds, 256);
+	    gethostname(Tcl_DStringValue(&ds), Tcl_DStringLength(&ds));
+	    Tcl_DStringSetLength(&ds, strlen(Tcl_DStringValue(&ds)));
 	}
     }
 
-    *encodingPtr = Tcl_GetEncoding(NULL, "utf-8");
+    *encodingPtr = Tcl_GetEncoding(NULL, NULL);
     *lengthPtr = Tcl_DStringLength(&ds);
     *valuePtr = (char *)ckalloc(*lengthPtr + 1);
     memcpy(*valuePtr, Tcl_DStringValue(&ds), *lengthPtr + 1);
     Tcl_DStringFree(&ds);
 }