diff --git a/api/src/org/labkey/api/exp/api/ExperimentService.java b/api/src/org/labkey/api/exp/api/ExperimentService.java
index 5e369154827..83e01403208 100644
--- a/api/src/org/labkey/api/exp/api/ExperimentService.java
+++ b/api/src/org/labkey/api/exp/api/ExperimentService.java
@@ -1155,6 +1155,8 @@ List<? extends ExpProtocol> getExpProtocolsWithParameterValue(
 
     Map<String, Map<String, Object>> getDomainMetrics();
 
+    boolean checkDuplicateName(@NotNull String newName, @NotNull TableInfo tableInfo);
+
     class XarExportOptions
     {
         String _lsidRelativizer = LSID_OPTION_FOLDER_RELATIVE;
diff --git a/experiment/src/org/labkey/experiment/ExpDataIterators.java b/experiment/src/org/labkey/experiment/ExpDataIterators.java
index 1bdb4385312..582ab33c544 100644
--- a/experiment/src/org/labkey/experiment/ExpDataIterators.java
+++ b/experiment/src/org/labkey/experiment/ExpDataIterators.java
@@ -2370,9 +2370,15 @@ else if (isMergeOrUpdate)
                 step2c = LoggingDataIterator.wrap(new ExpDataIterators.SampleStatusCheckIteratorBuilder(step2b, _container));
             }
 
+            DataIteratorBuilder step2d = step2c;
+            if (canUpdateNames && !dontUpdate.contains("name"))
+            {
+                step2d = LoggingDataIterator.wrap(new ExpDataIterators.DuplicateNameCheckIteratorBuilder(step2c, _propertiesTable));
+            }
+
             // Insert into exp.data then the provisioned table
             // Use embargo data iterator to ensure rows are committed before being sent along Issue 26082 (row at a time, reselect rowid)
-            DataIteratorBuilder step3 = LoggingDataIterator.wrap(new TableInsertDataIteratorBuilder(step2c, _expTable, _container)
+            DataIteratorBuilder step3 = LoggingDataIterator.wrap(new TableInsertDataIteratorBuilder(step2d, _expTable, _container)
                     .setKeyColumns(keyColumns)
                     .setDontUpdate(dontUpdate)
                     .setAddlSkipColumns(_excludedColumns)
@@ -3155,6 +3161,73 @@ public static void incrementCounts(Map<String, Integer> currentCounts, Map<Strin
         });
     }
 
+    public static class DuplicateNameCheckIteratorBuilder implements DataIteratorBuilder
+    {
+        private final DataIteratorBuilder _in;
+        private final TableInfo _tableInfo;
+
+        public DuplicateNameCheckIteratorBuilder(@NotNull DataIteratorBuilder in, TableInfo tableInfo)
+        {
+            _in = in;
+            _tableInfo = tableInfo;
+        }
+
+        @Override
+        public DataIterator getDataIterator(DataIteratorContext context)
+        {
+            DataIterator pre = _in.getDataIterator(context);
+            return LoggingDataIterator.wrap(new DuplicateNameCheckDataIterator(pre, context, _tableInfo));
+        }
+    }
+
+    public static class DuplicateNameCheckDataIterator extends WrapperDataIterator
+    {
+        final static String NAME_FIELD = "name";
+        private final DataIteratorContext _context;
+        private final Integer _nameCol;
+        private final TableInfo _tableInfo;
+
+        protected DuplicateNameCheckDataIterator(DataIterator di, DataIteratorContext context, TableInfo tableInfo)
+        {
+            super(di);
+            _context = context;
+            _tableInfo = tableInfo;
+            Map<String, Integer> map = DataIteratorUtil.createColumnNameMap(di);
+            _nameCol = map.get(NAME_FIELD);
+        }
+
+        @Override
+        public boolean next() throws BatchValidationException
+        {
+            boolean hasNext = super.next();
+            if (!hasNext)
+                return false;
+
+            if (_context.getErrors().hasErrors())
+                return hasNext;
+
+            if (_nameCol == null)
+                return hasNext;
+
+            Object nameObj = get(_nameCol);
+            if (nameObj == null)
+                return hasNext;
+
+            String newName = String.valueOf(nameObj);
+            if (StringUtils.isEmpty(newName))
+                return hasNext;
+
+            Map<String, Object> existingValues = getExistingRecord();
+            if (existingValues != null  && !existingValues.isEmpty() && existingValues.get(NAME_FIELD).equals(newName))
+                return hasNext;
+
+            if (ExperimentService.get().checkDuplicateName(newName, _tableInfo))
+                _context.getErrors().addRowError(new ValidationException(String.format("Name '%s' already exist.", newName)));
+
+            return hasNext;
+        }
+    }
+
     public static class SampleStatusCheckIteratorBuilder implements DataIteratorBuilder
     {
         private final DataIteratorBuilder _in;
diff --git a/experiment/src/org/labkey/experiment/api/ExpDataClassDataTableImpl.java b/experiment/src/org/labkey/experiment/api/ExpDataClassDataTableImpl.java
index 90408498d8b..bef3d49adeb 100644
--- a/experiment/src/org/labkey/experiment/api/ExpDataClassDataTableImpl.java
+++ b/experiment/src/org/labkey/experiment/api/ExpDataClassDataTableImpl.java
@@ -1323,6 +1323,11 @@ protected Map<String, Object> _update(User user, Container c, Map<String, Object
             String newName = (String) row.get(Name.name());
             String oldName = (String) oldRow.get(Name.name());
             boolean hasNameChange = !StringUtils.isEmpty(newName) && !newName.equals(oldName);
+            if (hasNameChange)
+            {
+                if (ExperimentServiceImpl.get().checkDuplicateName(newName, _dataClass.getTinfo()))
+                    throw new ValidationException(String.format("Name '%s' already exist.", newName));
+            }
 
             // Replace attachment columns with filename and keep AttachmentFiles
             Map<String, Object> rowStripped = new CaseInsensitiveHashMap<>();
diff --git a/experiment/src/org/labkey/experiment/api/ExperimentServiceImpl.java b/experiment/src/org/labkey/experiment/api/ExperimentServiceImpl.java
index c0e44cad601..317f9c0d8e1 100644
--- a/experiment/src/org/labkey/experiment/api/ExperimentServiceImpl.java
+++ b/experiment/src/org/labkey/experiment/api/ExperimentServiceImpl.java
@@ -9161,6 +9161,20 @@ public Map<String, Map<String, Object>> getDomainMetrics()
         return metrics;
     }
 
+    @Override
+    public boolean checkDuplicateName(@NotNull String newName, @NotNull TableInfo tableInfo)
+    {
+        SQLFragment dataRowSQL = new SQLFragment("SELECT name FROM ")
+                .append(tableInfo)
+                .append(" WHERE LOWER(name) = LOWER(?) AND name <> ?")
+                .add(newName)
+                .add(newName);
+        if (tableInfo.getSqlDialect().isSqlServer())
+            dataRowSQL.append(" COLLATE Latin1_General_BIN"); // force case sensitive comparison
+
+        return new SqlSelector(ExperimentService.get().getSchema(), dataRowSQL).exists();
+    }
+
     private Map<String, Object> getImportTemplatesMetrics()
     {
         DbSchema dbSchema = CoreSchema.getInstance().getSchema();
diff --git a/experiment/src/org/labkey/experiment/api/SampleTypeServiceImpl.java b/experiment/src/org/labkey/experiment/api/SampleTypeServiceImpl.java
index 1a6f7a2bad8..90c2e1e7aaa 100644
--- a/experiment/src/org/labkey/experiment/api/SampleTypeServiceImpl.java
+++ b/experiment/src/org/labkey/experiment/api/SampleTypeServiceImpl.java
@@ -118,6 +118,7 @@
 import java.util.Optional;
 import java.util.Set;
 import java.util.SortedSet;
+import java.util.TreeMap;
 import java.util.TreeSet;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -1699,7 +1700,7 @@ private Map<Integer, Pair<Integer, String>> getSampleAliquotCounts(Collection<In
                 .append(")-1 AS CreatedAliquotCount FROM exp.material AS m WHERE m.rowid\s");
         dialect.appendInClauseSql(sql, sampleIds);
 
-        Map<Integer, Pair<Integer, String>> sampleAliquotCounts = new HashMap<>();
+        Map<Integer, Pair<Integer, String>> sampleAliquotCounts = new TreeMap<>(); // Order sample by rowId to reduce probability of deadlock with search indexer
         try (ResultSet rs = new SqlSelector(dbSchema, sql).getResultSet())
         {
             while (rs.next())
@@ -1760,7 +1761,7 @@ SELECT RootMaterialRowId as rootRowId, COUNT(*) as aliquotCount
         }
         dialect.appendInClauseSql(sql, sampleIds);
 
-        Map<Integer, Pair<Integer, String>> sampleAliquotCounts = new HashMap<>();
+        Map<Integer, Pair<Integer, String>> sampleAliquotCounts = new TreeMap<>(); // Order by rowId to reduce deadlock with search indexer
         try (ResultSet rs = new SqlSelector(dbSchema, sql).getResultSet())
         {
             while (rs.next())
diff --git a/experiment/src/org/labkey/experiment/api/SampleTypeUpdateServiceDI.java b/experiment/src/org/labkey/experiment/api/SampleTypeUpdateServiceDI.java
index 0e12b71b23b..1b1ee775654 100644
--- a/experiment/src/org/labkey/experiment/api/SampleTypeUpdateServiceDI.java
+++ b/experiment/src/org/labkey/experiment/api/SampleTypeUpdateServiceDI.java
@@ -712,6 +712,12 @@ protected Map<String, Object> _update(User user, Container c, Map<String, Object
         if (hasNameChange && !NameExpressionOptionService.get().getAllowUserSpecificNamesValue(c))
             throw new ValidationException("User-specified sample name not allowed");
 
+        if (hasNameChange)
+        {
+            if (ExperimentServiceImpl.get().checkDuplicateName(newName, _sampleType.getTinfo()))
+                throw new ValidationException(String.format("Name '%s' already exist.", newName));
+        }
+
         String oldAliquotedFromLSID = (String) oldRow.get(AliquotedFromLSID.name());
         boolean isAliquot = !StringUtils.isEmpty(oldAliquotedFromLSID);