diff --git a/swh/loader/mercurial/from_disk.py b/swh/loader/mercurial/from_disk.py
--- a/swh/loader/mercurial/from_disk.py
+++ b/swh/loader/mercurial/from_disk.py
@@ -217,11 +217,12 @@
                 for revision in self.storage.revision_get(snapshot_branches)
                 if revision
             ]
-            self._latest_heads = [
-                hash_to_bytes(revision.metadata["node"])
-                for revision in revisions
-                if revision.metadata
-            ]
+            for revision in revisions:
+                if not revision.metadata:
+                    continue
+                hg_nodeid = hash_to_bytes(revision.metadata["node"])
+                self._latest_heads.append(hg_nodeid)
+                self._revision_nodeid_to_swhid[hg_nodeid] = revision.id
 
     def fetch_data(self) -> bool:
         """Fetch the data from the source the loader is currently loading
@@ -265,15 +266,9 @@
 
             # select revisions that are not ancestors of heads
             # and not the heads themselves
-            new_revs = repo.revs("not ::(%ld)", existing_heads)
-
-            # for now, reload all revisions if there are new commits
-            # otherwise the loader will crash on missing parents
-            # incremental loading will come in next commits
-            if new_revs:
-                return repo.revs("all()")
-            else:
-                return new_revs
+            revs = repo.revs("not ::(%ld)", existing_heads)
+            self.log.info(f"News revisions: {len(revs)}")
+            return revs
         else:
             return repo.revs("all()")
 
@@ -340,7 +335,7 @@
             "status": self._load_status,
         }
 
-    def get_revision_id_from_hg_nodeid(self, hg_nodeid: HgNodeId) -> Sha1Git:
+    def get_revision_id_from_hg_nodeid(self, hg_nodeid: HgNodeId) -> Optional[Sha1Git]:
         """Return the swhid of a revision given its hg nodeid.
 
         Args:
@@ -349,7 +344,9 @@
         Returns:
             the swhid of the revision.
         """
-        return self._revision_nodeid_to_swhid[hg_nodeid]
+        # TODO load from storage when research by hg node id is available
+        # Need: https://forge.softwareheritage.org/T2849
+        return self._revision_nodeid_to_swhid.get(hg_nodeid)
 
     def get_revision_parents(self, rev_ctx: hgutil.BaseContext) -> Tuple[Sha1Git, ...]:
         """Return the swhids of the parent revisions.
@@ -363,10 +360,20 @@
         parents = []
         for parent_ctx in rev_ctx.parents():
             parent_hg_nodeid = parent_ctx.node()
+
             # nullid is the value of a parent that does not exist
             if parent_hg_nodeid == hgutil.NULLID:
                 continue
-            parents.append(self.get_revision_id_from_hg_nodeid(parent_hg_nodeid))
+
+            sha1_git = self.get_revision_id_from_hg_nodeid(parent_hg_nodeid)
+
+            # parent not in storage from previous run
+            # and not previously loaded in current run
+            if sha1_git is None:
+                hg_nodeid = parent_hg_nodeid.hex()
+                raise ValueError(f"Cannot load revision with hg nodeid: {hg_nodeid}")
+
+            parents.append(sha1_git)
 
         return tuple(parents)
 
diff --git a/swh/loader/mercurial/tests/test_from_disk.py b/swh/loader/mercurial/tests/test_from_disk.py
--- a/swh/loader/mercurial/tests/test_from_disk.py
+++ b/swh/loader/mercurial/tests/test_from_disk.py
@@ -4,6 +4,7 @@
 # See top-level LICENSE file for more information
 
 import os
+import subprocess
 from datetime import datetime
 from hashlib import sha1
 
@@ -22,6 +23,12 @@
 from .loader_checker import ExpectedSwhids, LoaderChecker
 
 
+def hg_strip(repo: str, rev: str) -> None:
+    subprocess.check_call(
+        ["hg", "--config", "extensions.strip=", "strip", rev], cwd=repo
+    )
+
+
 def random_content() -> Content:
     """Create minimal content object."""
     data = str(datetime.now()).encode()
@@ -275,3 +282,42 @@
         "skipped_content": 0,
         "snapshot": 1,
     }
+
+
+def test_load_repo_with_new_commits(swh_config, datadir, tmp_path):
+    archive_name = "hello"
+    archive_path = os.path.join(datadir, f"{archive_name}.tgz")
+    json_path = os.path.join(datadir, f"{archive_name}.json")
+    repo_url = prepare_repository_from_archive(archive_path, archive_name, tmp_path)
+
+    # first load with missing commits
+    hg_strip(repo_url.replace("file://", ""), "tip")
+    loader = HgLoaderFromDisk(repo_url)
+    assert loader.load() == {"status": "eventful"}
+    assert get_stats(loader.storage) == {
+        "content": 2,
+        "directory": 2,
+        "origin": 1,
+        "origin_visit": 1,
+        "release": 0,
+        "revision": 2,
+        "skipped_content": 0,
+        "snapshot": 1,
+    }
+
+    # second load with all commits
+    repo_url = prepare_repository_from_archive(archive_path, archive_name, tmp_path)
+    loader = HgLoaderFromDisk(repo_url)
+    LoaderChecker(
+        loader=HgLoaderFromDisk(repo_url), expected=ExpectedSwhids.load(json_path),
+    ).check()
+    assert get_stats(loader.storage) == {
+        "content": 3,
+        "directory": 3,
+        "origin": 1,
+        "origin_visit": 2,
+        "release": 1,
+        "revision": 3,
+        "skipped_content": 0,
+        "snapshot": 2,
+    }