diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/ValueSetCheckerSimple.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/ValueSetCheckerSimple.java
index 4b1428ce3..4394866f5 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/ValueSetCheckerSimple.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/terminologies/ValueSetCheckerSimple.java
@@ -359,8 +359,13 @@ public class ValueSetCheckerSimple extends ValueSetWorker implements ValueSetChe
         }
         if (!inExpansion) {
           if (valueset != null && valueset.hasExpansion()) {
-            String msg = context.formatMessage(I18nConstants.CODESYSTEM_CS_UNK_EXPANSION, valueset.getUrl(), code.getCode().toString(), code.getSystem());
-            return new ValidationResult(IssueSeverity.ERROR, msg, makeIssue(IssueSeverity.ERROR, IssueType.NOTFOUND, path, msg));
+            String msg = context.formatMessage(I18nConstants.CODESYSTEM_CS_UNK_EXPANSION,
+                valueset.getUrl(), 
+                code.getSystem(), 
+                code.getCode().toString());
+            List<OperationOutcomeIssueComponent> issues = new ArrayList<>();
+            issues.addAll(makeIssue(IssueSeverity.ERROR, IssueType.NOTFOUND, path, msg));
+            throw new VSCheckerException(msg, issues);
           } else {
             List<OperationOutcomeIssueComponent> issues = new ArrayList<>();
             issues.addAll(makeIssue(IssueSeverity.ERROR, IssueType.NOTFOUND, path+".system", warningMessage));
diff --git a/org.hl7.fhir.utilities/src/main/resources/Messages.properties b/org.hl7.fhir.utilities/src/main/resources/Messages.properties
index f39e1f169..335d99003 100644
--- a/org.hl7.fhir.utilities/src/main/resources/Messages.properties
+++ b/org.hl7.fhir.utilities/src/main/resources/Messages.properties
@@ -720,7 +720,7 @@ SD_VALUE_TYPE_IILEGAL = The element {0} has a {1} of type {2}, which is not in t
 SD_VALUE_TYPE_REPEAT_HINT = The repeating element has a {1}. The {1} will apply to all the repeats (this has not been clear to all users)
 SD_VALUE_TYPE_REPEAT_WARNING_DOTNET = The repeating element has a {1} value for a primitive type. The DotNet validator will not apply this to all the repeats - this is an error
 SD_NO_TYPES_OR_CONTENTREF = The element {0} has no assigned types, and no content reference
-CODESYSTEM_CS_UNK_EXPANSION = The code provided ({2}) is not in the value set {0}, and a code is required from this value set. The system {1} is unknown.
+CODESYSTEM_CS_UNK_EXPANSION = The code provided ({2}) is not in the expansion in the value set {0}, and a code is required from this value set. The system {1} is unknown.
 BUNDLE_SEARCH_NOSELF = SearchSet Bundles should have a self link that specifies what the search was
 BUNDLE_SEARCH_SELF_NOT_UNDERSTOOD = No types could be determined from the search string, so the types can''t be checked
 BUNDLE_SEARCH_ENTRY_NO_RESOURCE = SearchSet Bundle Entries must have resources