diff --git a/src/routes/api/sender.js b/src/routes/api/sender.js
index 4d26407ae..404eb4a9b 100644
--- a/src/routes/api/sender.js
+++ b/src/routes/api/sender.js
@@ -4,6 +4,7 @@ const imageType = require('image-type');
 const imageService = require('../../services/image');
 const dateNoteService = require('../../services/date_notes');
 const noteService = require('../../services/notes');
+const attributeService = require('../../services/attributes');
 
 function uploadImage(req) {
     const file = req.file;
@@ -37,7 +38,7 @@ function saveNote(req) {
 
     if (req.body.labels) {
         for (const {name, value} of req.body.labels) {
-            note.setLabel(name, value);
+            note.setLabel(attributeService.sanitizeAttributeName(name), value);
         }
     }
 
diff --git a/src/services/attributes.js b/src/services/attributes.js
index d3e583fe2..d0383cbaa 100644
--- a/src/services/attributes.js
+++ b/src/services/attributes.js
@@ -2,7 +2,6 @@
 
 const repository = require('./repository');
 const sql = require('./sql');
-const utils = require('./utils');
 const Attribute = require('../entities/attribute');
 
 const ATTRIBUTE_TYPES = [ 'label', 'relation' ];
@@ -146,6 +145,20 @@ function getBuiltinAttributeNames() {
         ]);
 }
 
+function sanitizeAttributeName(origName) {
+    let fixedName;
+
+    if (origName === '') {
+        fixedName = "unnamed";
+    }
+    else {
+        // any not allowed character should be replaced with underscore
+        fixedName = origName.replace(/[^\p{L}\p{N}_:]/ug, "_");
+    }
+
+    return fixedName;
+}
+
 module.exports = {
     getNotesWithLabel,
     getNotesWithLabels,
@@ -156,5 +169,6 @@ module.exports = {
     getAttributeNames,
     isAttributeType,
     isAttributeDangerous,
-    getBuiltinAttributeNames
+    getBuiltinAttributeNames,
+    sanitizeAttributeName
 };
diff --git a/src/services/consistency_checks.js b/src/services/consistency_checks.js
index c36a02591..07c6d9679 100644
--- a/src/services/consistency_checks.js
+++ b/src/services/consistency_checks.js
@@ -11,6 +11,7 @@ const entityChangesService = require('./entity_changes.js');
 const optionsService = require('./options');
 const Branch = require('../entities/branch');
 const dateUtils = require('./date_utils');
+const attributeService = require('./attributes');
 
 class ConsistencyChecks {
     constructor(autoFix) {
@@ -607,20 +608,10 @@ class ConsistencyChecks {
     findWronglyNamedAttributes() {
         const attrNames = sql.getColumn(`SELECT DISTINCT name FROM attributes`);
 
-        const attrNameMatcher = new RegExp("^[\\p{L}\\p{N}_:]+$", "u");
-
         for (const origName of attrNames) {
-            if (!attrNameMatcher.test(origName)) {
-                let fixedName;
-
-                if (origName === '') {
-                    fixedName = "unnamed";
-                }
-                else {
-                    // any not allowed character should be replaced with underscore
-                    fixedName = origName.replace(/[^\p{L}\p{N}_:]/ug, "_");
-                }
+            const fixedName = attributeService.sanitizeAttributeName(origName);
 
+            if (fixedName !== origName) {
                 if (this.autoFix) {
                     // there isn't a good way to update this:
                     // - just SQL query will fix it in DB but not notify frontend (or other caches) that it has been fixed
diff --git a/src/services/image.js b/src/services/image.js
index 9420245e3..1fe432f5b 100644
--- a/src/services/image.js
+++ b/src/services/image.js
@@ -37,7 +37,7 @@ function getImageType(buffer) {
         }
     }
     else {
-        return imageType(buffer);
+        return imageType(buffer) || "jpg"; // optimistic JPG default
     }
 }
 
diff --git a/src/services/import/enex.js b/src/services/import/enex.js
index e80224af0..25171978d 100644
--- a/src/services/import/enex.js
+++ b/src/services/import/enex.js
@@ -7,6 +7,7 @@ const noteService = require("../notes");
 const imageService = require("../image");
 const protectedSessionService = require('../protected_session');
 const htmlSanitizer = require("../html_sanitizer");
+const attributeService = require("../attributes");
 
 // date format is e.g. 20181121T193703Z
 function parseDate(text) {
@@ -105,9 +106,17 @@ function importEnex(taskContext, file, parentNote) {
         const previousTag = getPreviousTag();
 
         if (previousTag === 'note-attributes') {
+            let labelName = currentTag;
+
+            if (labelName === 'source-url') {
+                labelName = 'sourceUrl';
+            }
+
+            labelName = attributeService.sanitizeAttributeName(labelName);
+
             note.attributes.push({
                 type: 'label',
-                name: currentTag,
+                name: labelName,
                 value: text
             });
         }
@@ -149,7 +158,7 @@ function importEnex(taskContext, file, parentNote) {
             } else if (currentTag === 'tag') {
                 note.attributes.push({
                     type: 'label',
-                    name: text,
+                    name: attributeService.sanitizeAttributeName(text),
                     value: ''
                 })
             }
@@ -227,6 +236,10 @@ function importEnex(taskContext, file, parentNote) {
         taskContext.increaseProgressCount();
 
         for (const resource of resources) {
+            if (!resource.content) {
+                continue;
+            }
+
             const hash = utils.md5(resource.content);
 
             const mediaRegex = new RegExp(`<en-media hash="${hash}"[^>]*>`, 'g');