diff --git a/packages/app-cli/tests/EnexToMd.ts b/packages/app-cli/tests/EnexToMd.ts
index 35d5d914d..0579b736b 100644
--- a/packages/app-cli/tests/EnexToMd.ts
+++ b/packages/app-cli/tests/EnexToMd.ts
@@ -113,4 +113,18 @@ describe('EnexToMd', function() {
 		expect(all[0].body).toBe('');
 	});
 
+	it('should handle invalid mime types', async () => {
+		// This is to handle the case where a resource has an invalid mime type,
+		// but that type can be determined from the filename. For example, in
+		// this thread, the ENEX file contains a "file.zip" file with a mime
+		// type "application/octet-stream", which can later cause problems to
+		// open the file.
+		// https://discourse.joplinapp.org/t/importing-a-note-with-a-zip-file/12123?u=laurent
+		const filePath = `${enexSampleBaseDir}/WithInvalidMime.enex`;
+		await importEnex('', filePath);
+		const all = await Resource.all();
+		expect(all.length).toBe(1);
+		expect(all[0].mime).toBe('application/zip');
+	});
+
 });
diff --git a/packages/app-cli/tests/enex_to_md/WithInvalidMime.enex b/packages/app-cli/tests/enex_to_md/WithInvalidMime.enex
new file mode 100644
index 000000000..8b2a94b13
--- /dev/null
+++ b/packages/app-cli/tests/enex_to_md/WithInvalidMime.enex
@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE en-export SYSTEM "http://xml.evernote.com/pub/evernote-export3.dtd">
+<en-export export-date="20201218T233722Z" application="Evernote" version="Evernote Mac 7.13 (458080)">
+<note><title>WithInvalidMime</title><content><![CDATA[<!DOCTYPE en-note SYSTEM "http://xml.evernote.com/pub/enml2.dtd"><en-note><div><en-media hash="d502aa19556b5b4b4dcceaf0514ad206" type="application/zip" style="cursor:pointer;" /></div><div><br /></div></en-note>]]></content><created>20201218T233549Z</created><updated>20201218T233706Z</updated><note-attributes><latitude>51.57516479492188</latitude><longitude>0.2281720315013734</longitude><altitude>29.71427536010742</altitude><author>laurent@cozic.net</author><source>desktop.mac</source><reminder-order>0</reminder-order></note-attributes><resource><data encoding="base64">UEsDBBQACAAIAJlyelEAAAAAAAAAAKAKAAAJACAAcGhvdG8uanBnVVQNAAfDub9fz7m/X8O5v191eAsA
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+by5qcGdVVA0AB8O5v1/Pub9fw7m/X3V4CwABBPUBAAAEFAAAAFBLBQYAAAAAAQABAFcAAADSCgAAAAA=
+</data><mime>application/octet-stream</mime><width>0</width><height>0</height><duration>0</duration><resource-attributes><timestamp>19700101T000000Z</timestamp><file-name>photo.zip</file-name></resource-attributes></resource></note>
+</en-export>
diff --git a/packages/lib/import-enex.js b/packages/lib/import-enex.js
index 4eda75be5..7ea2a1a6b 100644
--- a/packages/lib/import-enex.js
+++ b/packages/lib/import-enex.js
@@ -14,6 +14,7 @@ const md5 = require('md5');
 const { Base64Decode } = require('base64-stream');
 const md5File = require('md5-file');
 const shim = require('./shim').default;
+const { mime } = require('./mime-utils');
 
 // const Promise = require('promise');
 const fs = require('fs-extra');
@@ -514,11 +515,27 @@ function importEnex(parentFolderId, filePath, importOptions = null) {
 
 				noteAttributes = null;
 			} else if (n == 'resource') {
+				let mimeType = noteResource.mime ? noteResource.mime.trim() : '';
+
+				// Evernote sometimes gives an invalid or generic
+				// "application/octet-stream" mime type for files that could
+				// have a valid mime type, based on the extension. So in
+				// general, we trust the filename more than the provided mime
+				// type.
+				// https://discourse.joplinapp.org/t/importing-a-note-with-a-zip-file/12123
+				if (noteResource.filename) {
+					const mimeTypeFromFile = mime.fromFilename(noteResource.filename);
+					if (mimeTypeFromFile && mimeTypeFromFile !== mimeType) {
+						importOptions.onError(new Error(`Invalid mime type "${mimeType}" for resource "${noteResource.filename}". Using "${mimeTypeFromFile}" instead.`));
+						mimeType = mimeTypeFromFile;
+					}
+				}
+
 				note.resources.push({
 					id: noteResource.id,
 					dataFilePath: noteResource.dataFilePath,
 					dataEncoding: noteResource.dataEncoding,
-					mime: noteResource.mime ? noteResource.mime.trim() : '',
+					mime: mimeType,
 					title: noteResource.filename ? noteResource.filename.trim() : '',
 					filename: noteResource.filename ? noteResource.filename.trim() : '',
 					hasData: noteResource.hasData,