electron-userland · RobbieMinderhoud · Feb 23, 2026 · Feb 24, 2026 · Mar 5, 2026 · Mar 11, 2026
diff --git a/.changeset/rude-bottles-walk.md b/.changeset/rude-bottles-walk.md
@@ -0,0 +1,5 @@
+---
+"dmg-builder": patch
+---
+
+fix(dmg): use APFS as default filesystem for DMG builds due to incompatibilities on latest MacOS w/ HFS+
diff --git a/packages/app-builder-lib/scheme.json b/packages/app-builder-lib/scheme.json
@@ -898,6 +898,14 @@
           },
           "type": "array"
         },
+        "filesystem": {
+          "default": "APFS",
+          "description": "The filesystem for the DMG volume (e.g. `\"APFS\"` or `\"HFS+\"`). APFS is the default and recommended on macOS 10.13+.",
+          "type": [
+            "null",
+            "string"
+          ]
+        },
         "format": {
           "default": "UDZO",
           "description": "The disk image format. `ULFO` (lzfse-compressed image (OS X 10.11+ only)).",

diff --git a/packages/app-builder-lib/src/options/macOptions.ts b/packages/app-builder-lib/src/options/macOptions.ts
@@ -293,6 +293,12 @@ export interface DmgOptions extends TargetSpecificOptions {
    */
   format?: "UDRW" | "UDRO" | "UDCO" | "UDZO" | "UDBZ" | "ULFO"
 
+  /**
+   * The filesystem for the DMG volume (e.g. `"APFS"` or `"HFS+"`). APFS is the default and recommended on macOS 10.13+.
+   * @default APFS
+   */
+  readonly filesystem?: string | null
+
   /**
    * The initial size of the DMG filesystem. Accepts the same syntax as the `-size` argument to `hdiutil`, e.g. `"150m"`, `"4g"`.
    * If not specified, the size is calculated automatically.

diff --git a/packages/dmg-builder/src/dmg.ts b/packages/dmg-builder/src/dmg.ts
@@ -159,7 +159,7 @@ export class DmgTarget extends Target {
   // public to test
   async computeDmgOptions(appPath: string): Promise<DmgOptions> {
     const packager = this.packager
-    const specification: DmgOptions = { ...this.options }
+    const specification: DmgOptions = { ...this.options, filesystem: this.options.filesystem ?? "APFS" }
     if (specification.icon == null && specification.icon !== null) {
       specification.icon = await packager.getIconPath()
     }

diff --git a/packages/dmg-builder/src/dmgUtil.ts b/packages/dmg-builder/src/dmgUtil.ts
@@ -132,7 +132,7 @@ export async function customizeDmg({ appPath, artifactPath, volumeName, specific
     "text-size": iconTextSize,
 
     "compression-level": Number(process.env.ELECTRON_BUILDER_COMPRESSION_LEVEL || "9"),
-    // filesystem: specification.filesystem || "HFS+",
+    filesystem: specification.filesystem || "APFS",
     format: specification.format,
     size: specification.size,
     shrink: specification.shrink,

diff --git a/packages/electron-publish/src/gitlabPublisher.ts b/packages/electron-publish/src/gitlabPublisher.ts
@@ -121,9 +121,7 @@ export class GitlabPublisher extends HttpPublisher {
     const releaseName = this.releaseName || defaultName
     const branchName = await this.getDefaultBranch()
 
-    const description = this.releaseBody
-      ? trimStringWithWarn(this.releaseBody, 100000, "release body exceeds GitLab limit, truncating")
-      : `Release ${releaseName}`
+    const description = this.releaseBody ? trimStringWithWarn(this.releaseBody, 100000, "release body exceeds GitLab limit, truncating") : `Release ${releaseName}`
 
     const releaseData = {
       tag_name: this.tag,

diff --git a/packages/electron-publish/src/util.ts b/packages/electron-publish/src/util.ts
@@ -6,4 +6,4 @@ export const trimStringWithWarn = (str: string, maxLength: number, warnMessage:
   }
   log.warn({ length: str.length, maxLength }, warnMessage)
   return str.substring(0, maxLength)
-}
+}
diff --git a/test/snapshots/mac/dmgTest.js.snap b/test/snapshots/mac/dmgTest.js.snap
@@ -160,6 +160,7 @@ exports[`dmg > background color 1`] = `
       "y": 220,
     },
   ],
+  "filesystem": "APFS",
   "format": "UDRO",
   "title": "Bar",
   "writeUpdateInfo": false,

diff --git a/test/src/mac/dmgTest.ts b/test/src/mac/dmgTest.ts
@@ -127,9 +127,10 @@ describe.heavy.ifMac("dmg", { sequential: true }, () => {
             const totalBytes = stats.bsize * stats.blocks
 
             // 500m should give ~524,288,000 bytes (500 * 1024 * 1024)
-            // Allow margin for filesystem overhead (450MB to 600MB)
+            // Allow margin for filesystem overhead. APFS can report larger sizes than HFS+ due to
+            // different block sizing and allocation, so use a wide range (450MB–1GB).
             const minBytes = 450 * 1024 * 1024
-            const maxBytes = 600 * 1024 * 1024
+            const maxBytes = 1024 * 1024 * 1024
 
             expect(totalBytes).toBeGreaterThan(minBytes)
             expect(totalBytes).toBeLessThan(maxBytes)
-Original file line number
+Diff line change
@@ Expand Up @@
       }
       log.warn({ length: str.length, maxLength }, warnMessage)
       return str.substring(0, maxLength)
-    }
+    }