Index: /trunk/src/VBox/Main/src-server/MachineImplCloneVM.cpp
===================================================================
--- /trunk/src/VBox/Main/src-server/MachineImplCloneVM.cpp	(revision 37579)
+++ /trunk/src/VBox/Main/src-server/MachineImplCloneVM.cpp	(revision 37580)
@@ -35,5 +35,5 @@
 {
     ComPtr<IMedium>         pMedium;
-    uint64_t                uSize;
+    ULONG                   uWeight;
 }MEDIUMTASK;
 
@@ -48,5 +48,5 @@
     Guid                    snapshotUuid;
     Utf8Str                 strSaveStateFile;
-    uint64_t                cbSize;
+    ULONG                   uWeight;
 }SAVESTATETASK;
 
@@ -333,5 +333,5 @@
             rc = machine->COMGETTER(MediumAttachments)(ComSafeArrayAsOutParam(sfaAttachments));
             if (FAILED(rc)) throw rc;
-            /* Add all attachments (and there parents) of the different
+            /* Add all attachments (and their parents) of the different
              * machines to a worker list. */
             for (size_t a = 0; a < sfaAttachments.size(); ++a)
@@ -371,5 +371,5 @@
                     MEDIUMTASK mt;
                     mt.pMedium = pSrcMedium;
-                    mt.uSize   = lSize;
+                    mt.uWeight = (lSize + _1M - 1) / _1M;
                     mtc.chain.append(mt);
 
@@ -382,17 +382,19 @@
                  * diff image is small in size, it could need some time to create
                  * it. Adding the biggest size in the chain should balance this a
-                 * little bit more. */
-                int64_t uMaxSize = 0;
+                 * little bit more, i.e. the weight is the sum of the data which
+                 * needs to be read and written. */
+                uint64_t uMaxSize = 0;
                 for (size_t e = mtc.chain.size(); e > 0; --e)
                 {
                     MEDIUMTASK &mt = mtc.chain.at(e - 1);
+                    mt.uWeight += uMaxSize;
+
+                    /* Calculate progress data */
+                    ++uCount;
+                    uTotalWeight += mt.uWeight;
+
                     /* Save the max size for better weighting of diff image
                      * creation. */
-                    uMaxSize = RT_MAX(uMaxSize, mt.uSize);
-                    mt.uSize = (mt.uSize + uMaxSize) / 2;
-
-                    /* Calculate progress data */
-                    ++uCount;
-                    uTotalWeight += mt.uSize;
+                    uMaxSize = RT_MAX(uMaxSize, mt.uWeight);
                 }
                 d->llMedias.append(mtc);
@@ -406,10 +408,14 @@
                 sst.snapshotUuid     = machine->getSnapshotId();
                 sst.strSaveStateFile = bstrSrcSaveStatePath;
-                int vrc = RTFileQuerySize(sst.strSaveStateFile.c_str(), &sst.cbSize);
+                uint64_t cbSize;
+                int vrc = RTFileQuerySize(sst.strSaveStateFile.c_str(), &cbSize);
                 if (RT_FAILURE(vrc))
                     throw p->setError(VBOX_E_IPRT_ERROR, p->tr("Could not query file size of '%s' (%Rrc)"), sst.strSaveStateFile.c_str(), vrc);
+                /* same rule as above: count both the data which needs to
+                 * be read and written */
+                sst.uWeight = 2 * (cbSize + _1M - 1) / _1M;
                 d->llSaveStateFiles.append(sst);
                 ++uCount;
-                uTotalWeight += sst.cbSize;
+                uTotalWeight += sst.uWeight;
             }
         }
@@ -555,5 +561,5 @@
                 if (FAILED(rc)) throw rc;
 
-                rc = d->pProgress->SetNextOperation(BstrFmt(p->tr("Cloning Disk '%ls' ..."), bstrSrcName.raw()).raw(), mt.uSize);
+                rc = d->pProgress->SetNextOperation(BstrFmt(p->tr("Cloning Disk '%ls' ..."), bstrSrcName.raw()).raw(), mt.uWeight);
                 if (FAILED(rc)) throw rc;
 
@@ -709,5 +715,5 @@
 
             /* Move to next sub-operation. */
-            rc = d->pProgress->SetNextOperation(BstrFmt(p->tr("Copy save state file '%s' ..."), RTPathFilename(sst.strSaveStateFile.c_str())).raw(), sst.cbSize);
+            rc = d->pProgress->SetNextOperation(BstrFmt(p->tr("Copy save state file '%s' ..."), RTPathFilename(sst.strSaveStateFile.c_str())).raw(), sst.uWeight);
             if (FAILED(rc)) throw rc;
             /* Copy the file only if it was not copied already. */