diff --git a/public/app/features/alerting/unified/hooks/useFilteredRules.test.ts b/public/app/features/alerting/unified/hooks/useFilteredRules.test.ts
index db277cea39d..f6bbe0164f8 100644
--- a/public/app/features/alerting/unified/hooks/useFilteredRules.test.ts
+++ b/public/app/features/alerting/unified/hooks/useFilteredRules.test.ts
@@ -273,9 +273,25 @@ describe('filterRules', function () {
     const ruleQuery = '[alongnameinthefirstgroup][thishas spaces][somethingelse]';
     const namespaceQuery = 'foo|bar';
     const groupQuery = 'some|group';
+    const freeForm = '.+';
 
-    const performFilter = () =>
-      filterRules([ns], getFilter({ groupName: groupQuery, ruleName: ruleQuery, namespace: namespaceQuery }));
-    expect(performFilter).not.toThrow();
+    expect(() =>
+      filterRules(
+        [ns],
+        getFilter({ groupName: groupQuery, ruleName: ruleQuery, namespace: namespaceQuery, freeFormWords: [freeForm] })
+      )
+    ).not.toThrow();
+  });
+
+  // these test may same to be the same as the one above but it tests different edge-cases
+  it('does not crash with other regex values', () => {
+    const rules = [mockCombinedRule({ name: 'rule' })];
+
+    const ns = mockCombinedRuleNamespace({
+      name: 'namespace',
+      groups: [mockCombinedRuleGroup('group', rules)],
+    });
+
+    expect(() => filterRules([ns], getFilter({ freeFormWords: ['.+'] }))).not.toThrow();
   });
 });
diff --git a/public/app/features/alerting/unified/hooks/useFilteredRules.ts b/public/app/features/alerting/unified/hooks/useFilteredRules.ts
index f7674c92500..d515a79ab89 100644
--- a/public/app/features/alerting/unified/hooks/useFilteredRules.ts
+++ b/public/app/features/alerting/unified/hooks/useFilteredRules.ts
@@ -8,6 +8,7 @@ import { Matcher } from 'app/plugins/datasource/alertmanager/types';
 import { CombinedRuleGroup, CombinedRuleNamespace, Rule } from 'app/types/unified-alerting';
 import { isPromAlertingRuleState, PromRuleType, RulerGrafanaRuleDTO } from 'app/types/unified-alerting-dto';
 
+import { logError } from '../Analytics';
 import { applySearchFilterToQuery, getSearchFilterFromQuery, RulesFilter } from '../search/rulesSearchParser';
 import { labelsMatchMatchers, matcherToMatcherField } from '../utils/alertmanager';
 import { Annotation } from '../utils/constants';
@@ -28,6 +29,8 @@ import { useURLSearchParams } from './useURLSearchParams';
 const MAX_NEEDLE_SIZE = 25;
 const INFO_THRESHOLD = Infinity;
 
+const SEARCH_FAILED_ERR = new Error('Failed to search rules');
+
 /**
  * Escape query strings so that regex characters don't interfere
  * with uFuzzy search methods.
@@ -160,7 +163,20 @@ export const filterRules = (
   }
 
   // If a namespace and group have rules that match the rules filters then keep them.
-  return filteredNamespaces.reduce<CombinedRuleNamespace[]>(reduceNamespaces(filterState), []);
+  const filteredRuleNamespaces: CombinedRuleNamespace[] = [];
+
+  try {
+    const matches = filteredNamespaces.reduce<CombinedRuleNamespace[]>(reduceNamespaces(filterState), []);
+    matches.forEach((match) => {
+      filteredRuleNamespaces.push(match);
+    });
+  } catch {
+    logError(SEARCH_FAILED_ERR, {
+      search: JSON.stringify(filterState),
+    });
+  }
+
+  return filteredRuleNamespaces;
 };
 
 const reduceNamespaces = (filterState: RulesFilter) => {