User is encountering "This update cannot be previewed for unknown reason." when previewing an update set. - Support and Troubleshooting

User is encountering "This update cannot be previewed for unknown reason." when previewing an update set. Issue While previewing the updateset, you will get an error like "This update cannot be previewed for unknown reason."

Release Any Release

Cause During the preview process, the code evaluates the reference fields and any extensions of those referenced tables. One potential reason would be a broken table. You can identify the broken table by running the following script:

var td = GlideTableDescriptor.get("[Replace this with the table of the record from update set]"); var edList = td.getSchemaList();

for (var i = 0; i if (!edList.get(i).isReference()) continue;

var tableName = edList.get(i).getReference(); var gr = new GlideRecord(tableName);

gs.info("Table Name: " + tableName + " gr.isValid() = " + gr.isValid());

var extensionList = GlideDBObjectManager.get().getAllExtensions(tableName);

for (var j = 0; j var extendedTableName = extensionList.get(j); var gr = new GlideRecord(extendedTableName); gs.info("Extension of table " + tableName + ": " + extendedTableName + " gr.isValid() = " + gr.isValid()); }

gs.info("\n");

}

The problematic table will return false.

Resolution Check if you are still using the problematic table and request that you clean it up if not needed. For the update set itself, the workaround would be to export the XML for the affected record(s) from source instance and import them into the table in the target instance.