diff --git a/scan.c b/scan.c
index 84294f85..ea378945 100644
--- a/scan.c
+++ b/scan.c
@@ -97,6 +97,8 @@ static void scan_file_insert(struct snapraid_state* state, struct snapraid_disk*
 	block_pos = disk->first_free_block;
 	block_max = tommy_array_size(&disk->blockarr);
 	for(i=0;i<file->blockmax;++i) {
+		tommy_node* j;
+
 		/* find a free block */
 		while (block_pos < block_max && block_is_valid(tommy_array_get(&disk->blockarr, block_pos)))
 			++block_pos;
@@ -116,7 +118,18 @@ static void scan_file_insert(struct snapraid_state* state, struct snapraid_disk*
 		else
 			block_state_set(&file->blockvec[i], BLOCK_STATE_CHG);
 
-		/* store in the disk map */
+		/* invalidate the block of all the other disks */
+		for(j=state->disklist;j!=0;j=j->next) {
+			struct snapraid_disk* oth_disk = j->data;
+			struct snapraid_block* oth_block = disk_block_get(oth_disk, block_pos);
+
+			if (block_is_valid(oth_block)) {
+				/* remove the parity info for this block */
+				block_clear_parity(oth_block);
+			}
+		}
+
+		/* store in the disk map, after invalidating all the other blocks */
 		tommy_array_set(&disk->blockarr, block_pos, &file->blockvec[i]);
 	}
 	if (file->blockmax) {