diff --git a/static/js/research/panel.js b/static/js/research/panel.js
index 4f963d60d..d3d1ce760 100644
--- a/static/js/research/panel.js
+++ b/static/js/research/panel.js
@@ -941,13 +941,32 @@ function _exitHistorySelectMode() {
   _renderJobs();
 }
 
+async function _deleteResearchFromDisk(id) {
+  const response = await fetch(`${_apiBase}/api/research/${id}`, { method: 'DELETE', credentials: 'same-origin' });
+  if (!response.ok) throw new Error('Research deletion failed');
+}
+
+function _showDeleteFailure(count) {
+  if (typeof uiModule !== 'undefined' && uiModule?.showError) {
+    uiModule.showError(`Could not delete ${count} research ${count === 1 ? 'report' : 'reports'}. Please try again.`);
+  }
+}
+
 async function _deleteHistoryJobs(ids) {
   const selected = new Set(ids);
   const selectedJobs = jobs.getJobs().filter(job => selected.has(job.id));
-  await Promise.all(selectedJobs.filter(job => job.status === 'done').map(async job => {
-    try { await fetch(`${_apiBase}/api/research/${job.id}`, { method: 'DELETE', credentials: 'same-origin' }); } catch {}
+  let failed = 0;
+  await Promise.all(selectedJobs.map(async job => {
+    try {
+      if (job.status === 'done') await _deleteResearchFromDisk(job.id);
+      _historySelectedIds.delete(job.id);
+      jobs.removeJob(job.id);
+    } catch {
+      failed++;
+    }
   }));
-  selectedJobs.forEach(job => jobs.removeJob(job.id));
+  if (failed) _showDeleteFailure(failed);
+  return failed === 0;
 }
 
 async function _bulkDeleteHistory() {
@@ -957,8 +976,8 @@ async function _bulkDeleteHistory() {
     const ok = await window.styledConfirm(`Delete ${ids.length} research ${ids.length === 1 ? 'report' : 'reports'}?`, { confirmText: 'Delete', danger: true });
     if (!ok) return;
   }
-  await _deleteHistoryJobs(ids);
-  _exitHistorySelectMode();
+  if (await _deleteHistoryJobs(ids)) _exitHistorySelectMode();
+  else _updateHistoryBulkBar();
 }
 
 async function _clearHistory() {
@@ -1296,7 +1315,12 @@ function _buildJobCard(job) {
         const ok = await window.styledConfirm('Delete this research? This permanently removes it from disk.', { confirmText: 'Delete', danger: true });
         if (!ok) return;
       }
-      try { await fetch(`${_apiBase}/api/research/${job.id}`, { method: 'DELETE', credentials: 'same-origin' }); } catch {}
+      try {
+        await _deleteResearchFromDisk(job.id);
+      } catch {
+        _showDeleteFailure(1);
+        return;
+      }
       overflow.close();
       _animateOutThenRemove(card, () => jobs.removeJob(job.id));
     });
diff --git a/tests/test_research_history_delete_failures.py b/tests/test_research_history_delete_failures.py
new file mode 100644
index 000000000..c8974dd91
--- /dev/null
+++ b/tests/test_research_history_delete_failures.py
@@ -0,0 +1,103 @@
+"""History controllers must not dismiss reports the server failed to delete."""
+import json
+from pathlib import Path
+import shutil
+import subprocess
+
+import pytest
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+def _run(outcomes, *, bulk=False, clear=False, statuses=None):
+    if not shutil.which("node"):
+        pytest.skip("node is required to execute research controllers")
+    script = r"""
+const fs = require('fs'), vm = require('vm');
+const options = JSON.parse(process.argv[1]);
+const saved = new Map();
+const errors = [], calls = [];
+const context = {
+  localStorage: {getItem:k=>saved.get(k)||null, setItem:(k,v)=>saved.set(k,v)},
+  document: {getElementById:()=>null},
+  uiModule: {showError:message=>errors.push(message)},
+  window: {styledConfirm:async()=>true},
+  fetch: async (url, opts) => {
+    const id = url.split('/').pop();calls.push({id, method:opts.method, credentials:opts.credentials});
+    const outcome = options.outcomes[id] ?? 200;
+    if (outcome === 'network') throw new Error('scripted network failure');
+    return {ok:outcome>=200 && outcome<300, status:outcome};
+  },
+};
+vm.createContext(context);
+const jobs = fs.readFileSync('static/js/research/jobs.js','utf8');
+vm.runInContext(jobs.replace(/export /g, ''), context);
+vm.runInContext('globalThis.jobs = {getJobs,removeJob};', context);
+context.seed = Object.entries(options.statuses || {a:'done',b:'done',untouched:'done'}).map(([id,status])=>({id,status}));
+vm.runInContext('getJobs().push(...seed);', context);
+const panel = fs.readFileSync('static/js/research/panel.js','utf8');
+const start = panel.indexOf('function _updateHistoryBulkBar(');
+const end = panel.indexOf('function _renderJobs(', start);
+if (start < 0 || end < 0) throw new Error('history controller boundaries missing');
+vm.runInContext("_apiBase=''; let _historySelectMode=true; let _historySelectedIds=new Set(['a','b']); let _visibleHistoryIds=['a','b']; function _renderJobs(){};"+panel.slice(start,end), context);
+(async()=>{
+  const command = options.clear ? '_clearHistory()' : options.bulk ? '_bulkDeleteHistory()' : "_deleteHistoryJobs(['a','b'])";
+  await vm.runInContext(command, context);
+  console.log(JSON.stringify({
+    ids:vm.runInContext('getJobs().map(j=>j.id)',context),
+    selected:vm.runInContext('[..._historySelectedIds]',context),
+    selectionMode:vm.runInContext('_historySelectMode',context),
+    dismissed:JSON.parse(saved.get('odysseus-research-dismissed')||'[]'),
+    errors,calls,
+  }));
+})().catch(e=>{console.error(e);process.exitCode=1});
+"""
+    args = dict(outcomes=outcomes, bulk=bulk, clear=clear, statuses=statuses)
+    result = subprocess.run(["node", "-e", script, json.dumps(args)], cwd=ROOT,
+                            capture_output=True, text=True, timeout=30)
+    assert result.returncode == 0, result.stderr
+    return json.loads(result.stdout)
+
+
+@pytest.mark.parametrize("failure", [403, 404, 500, 503, "network"])
+def test_failed_reports_remain_visible_and_undismissed(failure):
+    result = _run({"a": failure, "b": failure})
+    assert result["ids"] == ["a", "b", "untouched"]
+    assert result["dismissed"] == []
+    assert len(result["errors"]) == 1
+    assert "2" in result["errors"][0]
+    assert all(call["method"] == "DELETE" and call["credentials"] == "same-origin"
+               for call in result["calls"])
+
+
+@pytest.mark.parametrize("failure", [500, "network"])
+def test_mixed_bulk_deletion_keeps_only_failed_selection_for_retry(failure):
+    result = _run({"a": 200, "b": failure}, bulk=True)
+    assert result["ids"] == ["b", "untouched"]
+    assert result["dismissed"] == ["a"]
+    assert result["selectionMode"] is True
+    assert result["selected"] == ["b"]
+    assert len(result["errors"]) == 1
+
+
+def test_successful_bulk_deletion_exits_selection():
+    result = _run({"a": 200, "b": 200}, bulk=True)
+    assert result["ids"] == ["untouched"]
+    assert result["selectionMode"] is False
+    assert result["selected"] == []
+    assert result["dismissed"] == ["a", "b"]
+    assert result["errors"] == []
+
+
+def test_local_failed_job_removal_needs_no_server_request():
+    result = _run({"a": 500}, statuses={"a": "error", "b": "cancelled"})
+    assert result["ids"] == []
+    assert result["calls"] == []
+    assert result["errors"] == []
+
+
+def test_clear_history_preserves_running_jobs_and_failed_deletions():
+    result = _run({"a": 500}, clear=True, statuses={"a": "done", "b": "running"})
+    assert result["ids"] == ["a", "b"]
+    assert result["dismissed"] == []
+    assert [call["id"] for call in result["calls"]] == ["a"]