diff --git a/src/config-import.js b/src/config-import.js
index e42d61b21..afd51262e 100644
--- a/src/config-import.js
+++ b/src/config-import.js
@@ -1,7 +1,7 @@
 import yauzl from 'yauzl-promise'
 import { validate, valueSchemas } from '@mapeo/schema'
 import { json, buffer } from 'node:stream/consumers'
-import { assert } from './utils.js'
+import { assert, isDefined } from './utils.js'
 import path from 'node:path'
 import { parse as parseBCP47 } from 'bcp-47'
 import { SUPPORTED_CONFIG_VERSION } from './constants.js'
@@ -172,15 +172,16 @@ export async function readConfig(configPath) {
         return sort - nextSort
       })
 
-      // check that preset references existing icon
       const iconFilenames = new Set(
-        iconEntries.map((icon) => {
-          const matches = path.basename(icon.filename).match(ICON_NAME_REGEX)
-          if (matches) {
-            const [_, name] = matches
-            return name
-          }
-        })
+        iconEntries
+          .map((icon) => {
+            const matches = path.basename(icon.filename).match(ICON_NAME_REGEX)
+            if (matches) {
+              const [_, name] = matches
+              return name
+            }
+          })
+          .filter(isDefined)
       )
 
       // 5. for each preset get the corresponding fieldId and iconId, add them to the db
diff --git a/src/utils.js b/src/utils.js
index 3d0ba9823..484c0ceb3 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -109,6 +109,15 @@ export function setHas(set) {
   return (value) => set.has(/** @type {*} */ (value))
 }
 
+/**
+ * @template T
+ * @param {undefined | T} value
+ * @returns {value is T}
+ */
+export function isDefined(value) {
+  return value !== undefined
+}
+
 /**
  * When reading from SQLite, any optional properties are set to `null`. This
  * converts `null` back to `undefined` to match the input types (e.g. the types
diff --git a/test-e2e/translation-api.js b/test-e2e/translation-api.js
index d41b24e37..bb94b925a 100644
--- a/test-e2e/translation-api.js
+++ b/test-e2e/translation-api.js
@@ -1,5 +1,6 @@
 import test from 'node:test'
 import assert from 'node:assert/strict'
+import { isDefined } from '../src/utils.js'
 import { createManagers, ManagerCustodian } from './utils.js'
 import { defaultConfigPath } from '../tests/helpers/default-config.js'
 import {
@@ -387,12 +388,3 @@ test('translation api - re-loading from disk', async (t) => {
 
   assert(hasExpectedNumberOfTranslations)
 })
-
-/**
- * @template T
- * @param {undefined | T} value
- * @returns {value is T}
- */
-function isDefined(value) {
-  return value !== undefined
-}
diff --git a/tests/utils.js b/tests/utils.js
index 804ba1e2d..13f2132b5 100644
--- a/tests/utils.js
+++ b/tests/utils.js
@@ -3,6 +3,7 @@ import assert from 'node:assert/strict'
 import {
   assert as utilsAssert,
   ExhaustivenessError,
+  isDefined,
   setHas,
 } from '../src/utils.js'
 
@@ -26,6 +27,12 @@ test('ExhaustivenessError', () => {
   })
 })
 
+test('isDefined()', () => {
+  assert(isDefined(123))
+  assert(isDefined(null))
+  assert(!isDefined(undefined))
+})
+
 test('setHas()', () => {
   const set = new Set([1, 2, 3])
   assert(setHas(set)(1))