diff --git a/misc/config_tools/scenario_config/jsonschema/converter.py b/misc/config_tools/scenario_config/jsonschema/converter.py
index 086aed148..8274c1bf0 100644
--- a/misc/config_tools/scenario_config/jsonschema/converter.py
+++ b/misc/config_tools/scenario_config/jsonschema/converter.py
@@ -151,6 +151,17 @@ class XS2JS:
         if '@acrn:widget-options' in annotation:
             js_ele['ui:options'] = eval(f"{{{annotation['@acrn:widget-options']}}}")
 
+    def convert_errormsg_config(self, annotation, js_ele):
+        if '@acrn:errormsg' in annotation:
+            opts = eval(f"{{{annotation['@acrn:errormsg']}}}")
+
+            # An items of an error schema requires an "err:" prefix.
+            keys = list(opts.keys())
+            for key in keys:
+                opts[f"err:{key}"] = opts.pop(key)
+
+            js_ele.update(opts)
+
     def xst2jst(self, type_name) -> str:
         """convert xml schema type name to json schema type name"""
         if type_name in self.xst2jst_mapping:
@@ -195,9 +206,10 @@ class XS2JS:
                             enum_names.append(enum_name)
                     js_st["enumNames"] = enum_names
 
-            # widget and its options
+            # widget configs and error messages
             if 'xs:annotation' in obj:
                 self.convert_widget_config(obj['xs:annotation'], js_st)
+                self.convert_errormsg_config(obj['xs:annotation'], js_st)
 
             js_st.update(self.xsa2jsa(restriction))
             return js_st
@@ -298,7 +310,7 @@ class XS2JS:
 
             if '@maxOccurs' in element:
                 # ui:options seen at this moment are copied from the annotation of the type.
-                possible_keys = ['type', '$ref', 'oneOf', 'ui:options']
+                possible_keys = ['type', '$ref', 'oneOf', 'ui:options', 'err:required', 'err:pattern']
                 convert_to_items_success = False
                 js_ele['items'] = {}
                 for possible_key in possible_keys:
@@ -353,6 +365,9 @@ class XS2JS:
                 # widget and its options
                 self.convert_widget_config(element['xs:annotation'], js_ele)
 
+                # Error messages
+                self.convert_errormsg_config(element['xs:annotation'], js_ele)
+
             properties[name] = js_ele
 
         # build result
diff --git a/misc/config_tools/schema/VMtypes.xsd b/misc/config_tools/schema/VMtypes.xsd
index c085370c4..24c71874e 100644
--- a/misc/config_tools/schema/VMtypes.xsd
+++ b/misc/config_tools/schema/VMtypes.xsd
@@ -71,12 +71,14 @@
 <xs:complexType name="EPCSection">
   <xs:sequence>
     <xs:element name="base" type="HexFormat" default="0">
-      <xs:annotation acrn:title="EPC section base" acrn:applicable-vms="pre-launched">
+      <xs:annotation acrn:title="EPC section base" acrn:applicable-vms="pre-launched"
+                     acrn:errormsg="'required': 'EPC section base is required.'">
         <xs:documentation>Specify the enclave page cache (EPC) section base for Intel Software Guard Extensions (SGX). Must be page aligned.</xs:documentation>
       </xs:annotation>
     </xs:element>
     <xs:element name="size" type="HexFormat" default="0">
-      <xs:annotation acrn:title="EPC section size (bytes)" acrn:applicable-vms="pre-launched">
+      <xs:annotation acrn:title="EPC section size (bytes)" acrn:applicable-vms="pre-launched"
+                     acrn:errormsg="'required': 'EPC section size is required.'">
         <xs:documentation>Specify the enclave page cache (EPC) section size in bytes for Intel Software Guard Extensions (SGX). Must be page aligned.</xs:documentation>
       </xs:annotation>
     </xs:element>
@@ -86,12 +88,14 @@
 <xs:complexType name="HPARegionType">
   <xs:sequence>
     <xs:element name="start_hpa" type="HexFormat">
-      <xs:annotation acrn:title="Start physical address">
+      <xs:annotation acrn:title="Start physical address"
+                     acrn:errormsg="'required': 'Physical memory base address is required.'">
         <xs:documentation>Specify the starting address for non-contiguous allocation.</xs:documentation>
       </xs:annotation>
     </xs:element>
     <xs:element name="size_hpa" type="xs:integer">
-      <xs:annotation acrn:title="Size (MB)">
+      <xs:annotation acrn:title="Size (MB)"
+                     acrn:errormsg="'required': 'Physical memory size is required.'">
         <xs:documentation>Specify the physical memory size for non-contiguous allocation in megabytes.
 The size is a subset of the VM's total memory size specified on the Basic tab.</xs:documentation>
         </xs:annotation>
@@ -278,7 +282,8 @@ The size is a subset of the VM's total memory size specified on the Basic tab.</
   <xs:sequence>
     <xs:element name="usb_dev" type="xs:string" minOccurs="0" maxOccurs="unbounded">
       <xs:annotation acrn:title="USB device assignment"
-	  acrn:options="//usb_device/@description" acrn:options-sorted-by="lambda s: s">
+                     acrn:options="//usb_device/@description" acrn:options-sorted-by="lambda s: s"
+                     acrn:errormsg="'required': 'USB device required. If no USB device is available, click the X at the top right corner of this entry to remove.'">
         <xs:documentation>Select the USB physical bus and port number that will be emulated by the ACRN Device Model for this VM. USB 3.0, 2.0, and 1.0 are supported.</xs:documentation>
       </xs:annotation>
     </xs:element>
diff --git a/misc/config_tools/schema/config.xsd b/misc/config_tools/schema/config.xsd
index b7b191a1e..0c70660b0 100644
--- a/misc/config_tools/schema/config.xsd
+++ b/misc/config_tools/schema/config.xsd
@@ -124,7 +124,8 @@
 <xs:complexType name="MemoryOptionsType">
   <xs:all>
     <xs:element name="STACK_SIZE" type="HexFormat" default="0x2000">
-      <xs:annotation acrn:title="CPU memory stack size (bytes)" acrn:views="advanced">
+      <xs:annotation acrn:title="CPU memory stack size (bytes)" acrn:views="advanced"
+                     acrn:errormsg="'required': 'Stack size is required.'">
         <xs:documentation>Specify the size of the memory stack in bytes for each physical CPU. For example, if you specify 8 kilobytes, each CPU will get its own 8-kilobyte stack.</xs:documentation>
       </xs:annotation>
     </xs:element>
@@ -299,9 +300,10 @@ Refer to :ref:`vuart_config` for detailed vUART settings.</xs:documentation>
       </xs:annotation>
     </xs:element>
     <xs:element name="name" type="VMNameType">
-        <xs:annotation acrn:title="VM name" acrn:views="basic">
-          <xs:documentation>Specify the name used to identify this VM. The VM name will be shown in the hypervisor console vm_list command.</xs:documentation>
-        </xs:annotation>
+      <xs:annotation acrn:title="VM name" acrn:views="basic"
+                     acrn:errormsg="'required': 'VM name is required.'">
+        <xs:documentation>Specify the name used to identify this VM. The VM name will be shown in the hypervisor console vm_list command.</xs:documentation>
+      </xs:annotation>
     </xs:element>
     <xs:element name="vm_type" type="VMType" minOccurs="0">
       <xs:annotation acrn:title="VM type" acrn:views="basic">
@@ -484,8 +486,9 @@ mouse, and tablet.  It sends Linux input layer events over virtio.</xs:documenta
               <xs:documentation>The virtio-blk device presents a block device to the VM. Each virtio-blk device appears as a disk inside the VM.</xs:documentation>
             </xs:annotation>
               <xs:simpleType>
-                  <xs:annotation acrn:widget-options="'placeholder': '/home/user/path/to/disk.image'" />
-                  <xs:restriction base="xs:string" />
+                <xs:annotation acrn:widget-options="'placeholder': '/home/user/path/to/disk.image'"
+                               acrn:errormsg="'required': 'Path to a disk image required.'"/>
+                <xs:restriction base="xs:string" />
               </xs:simpleType>
           </xs:element>
         </xs:all>
diff --git a/misc/config_tools/schema/types.xsd b/misc/config_tools/schema/types.xsd
index b77e46b43..e4e7eefc0 100644
--- a/misc/config_tools/schema/types.xsd
+++ b/misc/config_tools/schema/types.xsd
@@ -14,7 +14,8 @@
 </xs:simpleType>
 
 <xs:simpleType name="HexFormat">
-  <xs:annotation acrn:widget-options="'placeholder': 'A hexadecimal number with a leading 0x, e.g. 0x1000.'">
+  <xs:annotation acrn:widget-options="'placeholder': 'A hexadecimal number with a leading 0x, e.g. 0x1000.'"
+                 acrn:errormsg="'pattern': 'Must be a hexadecimal integer (case-insensitive).'">
     <xs:documentation>An Integer value in hexadecimal format (with a leading ``0x``).</xs:documentation>
   </xs:annotation>
   <xs:restriction base="xs:string">
@@ -167,7 +168,8 @@ Read more about the available scheduling options in :ref:`cpu_sharing`.</xs:docu
 </xs:simpleType>
 
 <xs:simpleType name="VMNameType">
-  <xs:annotation acrn:widget-options="'placeholder': 'A string with at most 15 non-space characters, e.g. Linux-VM-1.'">
+  <xs:annotation acrn:widget-options="'placeholder': 'A string with at most 15 non-space characters, e.g. Linux-VM-1.'"
+                 acrn:errormsg="'pattern': 'Must NOT be longer than 15 characters or contain characters other than letters, digits, \'_\' and \'-\'.'">
     <xs:documentation>A string of up to 15 letters, digits, ``_``, or ``-``.</xs:documentation>
   </xs:annotation>
   <xs:restriction base="xs:string">