diff --git a/packages/backend/src/misc/populate-emojis.ts b/packages/backend/src/misc/populate-emojis.ts
index 870dff5cf..b2488e66f 100644
--- a/packages/backend/src/misc/populate-emojis.ts
+++ b/packages/backend/src/misc/populate-emojis.ts
@@ -41,13 +41,10 @@ function normalizeHost(
 }
 
 function parseEmojiStr(emojiName: string, noteUserHost: string | null) {
-	const match = emojiName.match(/^(\w+)(?:@([\w.-]+))?$/);
-	if (!match) return { name: null, host: null };
-
-	const name = match[1];
-
-	// ホスト正規化
-	const host = toPunyNullable(normalizeHost(match[2], noteUserHost));
+	// emojiName may be of the form `emoji@host`, turn it into a suitable form
+	const match = emojiName.split("@");
+	const name = match[0];
+	const host = toPunyNullable(normalizeHost(match[1], noteUserHost));
 
 	return { name, host };
 }
diff --git a/packages/backend/src/queue/processors/db/export-custom-emojis.ts b/packages/backend/src/queue/processors/db/export-custom-emojis.ts
index 7a19d0b60..1374d6c4e 100644
--- a/packages/backend/src/queue/processors/db/export-custom-emojis.ts
+++ b/packages/backend/src/queue/processors/db/export-custom-emojis.ts
@@ -68,7 +68,9 @@ export async function exportCustomEmojis(
 
 	for (const emoji of customEmojis) {
 		const ext = mime.extension(emoji.type);
-		const fileName = emoji.name + (ext ? `.${ext}` : "");
+		// there are some restrictions on file names, so to be safe the files are
+		// named after their database id instead of the actual emoji name
+		const fileName = emoji.id + (ext ? '.' + ext : '');
 		const emojiPath = `${path}/${fileName}`;
 		fs.writeFileSync(emojiPath, "", "binary");
 		let downloaded = false;