diff --git a/lib/galaxy/tool_source_store/populator.py b/lib/galaxy/tool_source_store/populator.py
index b0bcfe9f401..2f99545406a 100644
--- a/lib/galaxy/tool_source_store/populator.py
+++ b/lib/galaxy/tool_source_store/populator.py
@@ -60,6 +60,7 @@ from galaxy.tool_source_store.index import (
     ToolIndexEntry,
 )
 from galaxy.tool_util.parser import get_tool_source
+from galaxy.tool_util.parser.util import parse_tool_version_with_defaults
 from galaxy.tool_util.toolbox.parser import get_toolbox_parser
 
 log = logging.getLogger(__name__)
@@ -435,10 +436,20 @@ def build_index_entry_from_source(
             except Exception:
                 pass
 
+        # Honour the same version-default rules as ``Tool.__init__``: empty
+        # ``version`` on a pre-16.04-profile tool becomes "1.0.0"; on newer
+        # profiles it raises. Without this, ``ToolLineage.register_version``
+        # crashes on ``Version(None)`` during the eager walk.
+        try:
+            version = parse_tool_version_with_defaults(tool_id, tool_source)
+        except Exception as e:
+            log.warning("parse_tool_version_with_defaults raised for %s: %s", tool_id, e)
+            version = tool_source.parse_version() or "0"
+
         return ToolIndexEntry(
             id=tool_id,
             uuid=uuid_val,
-            version=tool_source.parse_version(),
+            version=version,
             name=tool_source.parse_name() or "",
             description=tool_source.parse_description() or "",
             panel_section_id=discovered.section_id,
diff --git a/lib/galaxy/tools/lazy_toolbox.py b/lib/galaxy/tools/lazy_toolbox.py
index f8ec4fac0f9..435fc9abaf9 100644
--- a/lib/galaxy/tools/lazy_toolbox.py
+++ b/lib/galaxy/tools/lazy_toolbox.py
@@ -249,13 +249,22 @@ class LazyTool:
     def to_dict(self, trans=None, link_details: bool = False, tool_help: bool = False, **kw) -> dict[str, Any]:
         """API serialisation. ``link_details=False`` stays on the entry fast path.
 
-        ``link_details=True`` (used by ``/api/tools/<id>/build``) needs the full
-        :meth:`Tool.to_dict` payload (parameters, citations, ...). That triggers
-        materialise. The default and EDAM panel listings call with
-        ``link_details=False`` and stay cheap.
+        ``link_details=True`` (used by ``/api/tools/<id>/build`` and the panel
+        view walk) needs the full :meth:`Tool.to_dict` payload (parameters,
+        citations, ...). That triggers materialise. If materialise raises
+        (tool XML with options/filters the parser can't handle —
+        ``upload_dataset``, ``column="value"`` against an unresolvable
+        column-name spec, …), fall back to the entry-only fast-path dict so
+        the panel listing still renders. The eager toolbox catches the same
+        errors at boot in ``_load_tool_tag_set`` and drops the tool from
+        ``_tools_by_id``; we surface them lazily and degrade gracefully
+        instead.
         """
         if link_details:
-            return self._materialize().to_dict(trans, link_details=True, tool_help=tool_help, **kw)
+            try:
+                return self._materialize().to_dict(trans, link_details=True, tool_help=tool_help, **kw)
+            except Exception as e:
+                log.warning("LazyTool.to_dict: materialise failed for %s, falling back to entry: %s", self.id, e)
         entry = self._entry
         return {
             "id": self.id,