diff --git a/packages/local-sync/src/message-processor/extract-files.js b/packages/local-sync/src/message-processor/extract-files.js
index de939cdaf..cb302c9c1 100644
--- a/packages/local-sync/src/message-processor/extract-files.js
+++ b/packages/local-sync/src/message-processor/extract-files.js
@@ -7,12 +7,22 @@ function collectFilesFromStruct({db, message, struct, fileIds = new Set()}) {
       collected = collected.concat(collectFilesFromStruct({db, message, struct: part, fileIds}));
     } else {
       const disposition = part.disposition || {}
-      const isAttachment = /attachment/gi.test(disposition.type);
+      const filename = (disposition.params || {}).filename;
+
+      // Note that the contentId is stored in part.id, while the MIME part id
+      // is stored in part.partID
+      const match = /^<(.*)>$/.exec(part.id) // extract id from <id>
+      const contentId = match ? match[1] : part.id;
+
+      // Check if the part is an attachment. If it's inline, we also need
+      // to ensure that there is a filename and contentId because some clients
+      // use "inline" for text in the body.
+      const isAttachment = /(attachment)/gi.test(disposition.type) ||
+        (/(inline)/gi.test(disposition.type) && filename && contentId);
 
       if (!isAttachment) continue
 
       const partId = part.partID
-      const filename = (disposition.params || {}).filename;
       const fileId = `${message.id}-${partId}-${part.size}`
       if (!fileIds.has(fileId)) {
         collected.push(File.build({
@@ -24,6 +34,7 @@ function collectFilesFromStruct({db, message, struct, fileIds = new Set()}) {
           messageId: message.id,
           accountId: message.accountId,
           contentType: `${part.type}/${part.subtype}`,
+          contentId,
         }));
         fileIds.add(fileId)
       }
diff --git a/packages/local-sync/src/models/file.js b/packages/local-sync/src/models/file.js
index 3eec65872..4cc63e38a 100644
--- a/packages/local-sync/src/models/file.js
+++ b/packages/local-sync/src/models/file.js
@@ -12,6 +12,7 @@ module.exports = (sequelize, Sequelize) => {
     messageId: { type: Sequelize.STRING, allowNull: false },
     accountId: { type: Sequelize.STRING, allowNull: false },
     contentType: Sequelize.STRING(500),
+    contentId: Sequelize.STRING(500),
   }, {
     indexes: [
       {fields: ['messageId']},
@@ -54,6 +55,7 @@ module.exports = (sequelize, Sequelize) => {
           message_id: this.messageId,
           account_id: this.accountId,
           content_type: this.contentType,
+          content_id: this.contentId,
         };
       },
     },