--- trunk/src/brains/BlockSnapshotManager.cpp	2013/06/16 15:15:42	1879
+++ trunk/src/brains/BlockSnapshotManager.cpp	2014/01/16 16:00:43	1964
@@ -76,6 +76,9 @@ namespace OpenMD {
       // number of frames in each block given the need to hold multiple blocks 
       // in memory at the same time:
       nSnapshotPerBlock_ = int(frameCapacity) / blockCapacity_;
+      if (nSnapshotPerBlock_ <= 0) {
+       std::cerr << "not enough memory to hold two configs!" << std::endl;
+      }
       reader_ = new DumpReader(info, filename);
       nframes_ = reader_->getNFrames();
       int nblocks = nframes_ / nSnapshotPerBlock_;
@@ -175,6 +178,10 @@ namespace OpenMD {
 	//in case, unloadBlock called multiple times
 	activeRefCount_[i - activeBlocks_.begin()]  = 0;
       }
+
+      if (activeRefCount_[i-activeBlocks_.begin()] == 0) {
+        internalUnload(block);
+      }
         
       unloadSuccess = true;
     } else {
@@ -198,6 +205,7 @@ namespace OpenMD {
   }
 
   void BlockSnapshotManager::internalUnload(int block) {
+    std::cerr << "called internal unload for block "<< block << "\n";
     for (int i = blocks_[block].first; i < blocks_[block].second; ++i) {
       delete snapshots_[i];
       snapshots_[i] = NULL;