diff --git a/packages/nylas-core/imap-box.js b/packages/nylas-core/imap-box.js
new file mode 100644
index 000000000..ec9283749
--- /dev/null
+++ b/packages/nylas-core/imap-box.js
@@ -0,0 +1,156 @@
+const _ = require('underscore');
+
+const {
+  IMAPConnectionNotReadyError,
+} = require('./imap-errors');
+
+class IMAPBox {
+  constructor(imapConn, box) {
+    this._conn = imapConn
+    this._box = box
+
+    return new Proxy(this, {
+      get(target, name) {
+        const prop = Reflect.get(target, name)
+        if (!prop) {
+          return Reflect.get(target._box, name)
+        }
+        if (_.isFunction(prop) && target._conn._imap._box.name !== target._box.name) {
+          return () => Promise.reject(
+            new Error(`IMAPBox::${name} - Can't operate on a mailbox that is no longer open on the current IMAPConnection.`)
+          )
+        }
+        return prop
+      },
+    })
+  }
+
+  /**
+   * @param {array|string} range - can be a single message identifier,
+   * a message identifier range (e.g. '2504:2507' or '*' or '2504:*'),
+   * an array of message identifiers, or an array of message identifier ranges.
+   * @return {Observable} that will feed each message as it becomes ready
+   */
+  fetchEach(range, options, forEachMessageCallback) {
+    if (!options) {
+      throw new Error("IMAPBox.fetch now requires an options object.")
+    }
+    if (range.length === 0) {
+      return Promise.resolve()
+    }
+
+    return this._conn.createConnectionPromise((resolve, reject) => {
+      const f = this._conn._imap.fetch(range, options);
+      f.on('message', (imapMessage) => {
+        const parts = {};
+        let headers = null;
+        let attributes = null;
+        imapMessage.on('attributes', (attrs) => {
+          attributes = attrs;
+        });
+        imapMessage.on('body', (stream, info) => {
+          const chunks = [];
+
+          stream.on('data', (chunk) => {
+            chunks.push(chunk);
+          });
+
+          stream.once('end', () => {
+            const full = Buffer.concat(chunks).toString('utf8');
+            if (info.which === 'HEADER') {
+              headers = full;
+            } else {
+              parts[info.which] = full;
+            }
+          });
+        });
+        imapMessage.once('end', () => {
+          forEachMessageCallback({attributes, headers, parts});
+        });
+      })
+      f.once('error', reject);
+      f.once('end', resolve);
+    });
+  }
+
+  /**
+   * @return {Promise} that resolves to requested message
+   */
+  fetchMessage(uid) {
+    if (!uid) {
+      throw new Error("IMAPConnection.fetchMessage requires a message uid.")
+    }
+    return this.fetchEach([uid], {
+      bodies: ['HEADER', 'TEXT'],
+    })
+  }
+
+  fetchMessageStream(uid, options) {
+    if (!uid) {
+      throw new Error("IMAPConnection.fetchStream requires a message uid.")
+    }
+    if (!options) {
+      throw new Error("IMAPConnection.fetchStream requires an options object.")
+    }
+    return this._conn.createConnectionPromise((resolve, reject) => {
+      const f = this._conn._imap.fetch(uid, options);
+      f.on('message', (imapMessage) => {
+        imapMessage.on('body', (stream) => {
+          resolve(stream)
+        })
+      })
+      f.once('error', reject)
+    })
+  }
+
+  /**
+   * @param {array|string} range - can be a single message identifier,
+   * a message identifier range (e.g. '2504:2507' or '*' or '2504:*'),
+   * an array of message identifiers, or an array of message identifier ranges.
+   * @return {Promise} that resolves to a map of uid -> attributes for every
+   * message in the range
+   */
+  fetchUIDAttributes(range) {
+    return this._conn.createConnectionPromise((resolve, reject) => {
+      const attributesByUID = {};
+      const f = this._conn._imap.fetch(range, {});
+      f.on('message', (msg) => {
+        msg.on('attributes', (attrs) => {
+          attributesByUID[attrs.uid] = attrs;
+        })
+      });
+      f.once('error', reject);
+      f.once('end', () => resolve(attributesByUID));
+    });
+  }
+
+  addFlags(range, flags) {
+    if (!this._conn._imap) {
+      throw new IMAPConnectionNotReadyError(`IMAPBox::addFlags`)
+    }
+    return this._conn._imap.addFlagsAsync(range, flags)
+  }
+
+  delFlags(range, flags) {
+    if (!this._conn._imap) {
+      throw new IMAPConnectionNotReadyError(`IMAPBox::delFlags`)
+    }
+    return this._conn._imap.delFlagsAsync(range, flags)
+  }
+
+  moveFromBox(range, folderName) {
+    if (!this._conn._imap) {
+      throw new IMAPConnectionNotReadyError(`IMAPBox::moveFromBox`)
+    }
+    return this._conn._imap.moveAsync(range, folderName)
+  }
+
+  closeBox({expunge = true} = {}) {
+    if (!this._conn._imap) {
+      throw new IMAPConnectionNotReadyError(`IMAPBox::closeBox`)
+    }
+    return this._conn._imap.closeBoxAsync(expunge)
+  }
+}
+
+module.exports = IMAPBox;
diff --git a/packages/nylas-core/imap-connection.js b/packages/nylas-core/imap-connection.js
index bbbef526f..8c37acd28 100644
--- a/packages/nylas-core/imap-connection.js
+++ b/packages/nylas-core/imap-connection.js
@@ -1,163 +1,13 @@
-const Rx = require('rx')
 const Imap = require('imap');
 const _ = require('underscore');
 const xoauth2 = require('xoauth2');
 const EventEmitter = require('events');
 
-class IMAPConnectionNotReadyError extends Error {
-  constructor(funcName) {
-    super(`${funcName} - You must call connect() first.`);
-
-    // hack so that the error matches the ones used by node-imap
-    this.source = 'socket';
-  }
-}
-
-class IMAPBox {
-
-  constructor(imapConn, box) {
-    this._imap = imapConn
-    this._box = box
-    return new Proxy(this, {
-      get(target, name) {
-        const prop = Reflect.get(target, name)
-        if (!prop) {
-          return Reflect.get(target._box, name)
-        }
-        if (_.isFunction(prop) && target._imap._box.name !== target._box.name) {
-          return () => Promise.reject(
-            new Error(`IMAPBox::${name} - Can't operate on a mailbox that is no longer open on the current IMAPConnection.`)
-          )
-        }
-        return prop
-      },
-    })
-  }
-
-  /**
-   * @param {array|string} range - can be a single message identifier,
-   * a message identifier range (e.g. '2504:2507' or '*' or '2504:*'),
-   * an array of message identifiers, or an array of message identifier ranges.
-   * @return {Observable} that will feed each message as it becomes ready
-   */
-  fetch(range, options) {
-    if (!options) {
-      throw new Error("IMAPBox.fetch now requires an options object.")
-    }
-    if (range.length === 0) {
-      return Rx.Observable.empty()
-    }
-    return Rx.Observable.create((observer) => {
-      const f = this._imap.fetch(range, options);
-      f.on('message', (imapMessage) => {
-        const parts = {};
-        let headers = null;
-        let attributes = null;
-        imapMessage.on('attributes', (attrs) => {
-          attributes = attrs;
-        });
-        imapMessage.on('body', (stream, info) => {
-          const chunks = [];
-
-          stream.on('data', (chunk) => {
-            chunks.push(chunk);
-          });
-
-          stream.once('end', () => {
-            const full = Buffer.concat(chunks).toString('utf8');
-            if (info.which === 'HEADER') {
-              headers = full;
-            } else {
-              parts[info.which] = full;
-            }
-          });
-        });
-        imapMessage.once('end', () => {
-          observer.onNext({attributes, headers, parts});
-        });
-      })
-      f.once('error', (error) => observer.onError(error))
-      f.once('end', () => observer.onCompleted())
-    })
-  }
-
-  fetchStream({uid, options}) {
-    if (!uid) {
-      throw new Error("IMAPConnection.fetchStream requires a message uid.")
-    }
-    if (!options) {
-      throw new Error("IMAPConnection.fetchStream requires an options object.")
-    }
-    return new Promise((resolve, reject) => {
-      const f = this._imap.fetch(uid, options);
-      f.on('message', (imapMessage) => {
-        imapMessage.on('body', (stream) => {
-          resolve(stream)
-        })
-      })
-      f.once('error', reject)
-    })
-  }
-
-  /**
-   * @return {Promise} that resolves to requested message
-   */
-  fetchMessage(uid) {
-    return this.fetch([uid], {
-      bodies: ['HEADER', 'TEXT'],
-    }).toPromise()
-  }
-
-  /**
-   * @param {array|string} range - can be a single message identifier,
-   * a message identifier range (e.g. '2504:2507' or '*' or '2504:*'),
-   * an array of message identifiers, or an array of message identifier ranges.
-   * @return {Promise} that resolves to a map of uid -> attributes for every
-   * message in the range
-   */
-  fetchUIDAttributes(range) {
-    return new Promise((resolve, reject) => {
-      const attributesByUID = {};
-      const f = this._imap.fetch(range, {});
-      f.on('message', (msg) => {
-        msg.on('attributes', (attrs) => {
-          attributesByUID[attrs.uid] = attrs;
-        })
-      });
-      f.once('error', reject);
-      f.once('end', () => resolve(attributesByUID));
-    });
-  }
-
-  addFlags(range, flags) {
-    if (!this._imap) {
-      throw new IMAPConnectionNotReadyError(`IMAPBox::addFlags`)
-    }
-    return this._imap.addFlagsAsync(range, flags)
-  }
-
-  delFlags(range, flags) {
-    if (!this._imap) {
-      throw new IMAPConnectionNotReadyError(`IMAPBox::delFlags`)
-    }
-    return this._imap.delFlagsAsync(range, flags)
-  }
-
-  moveFromBox(range, folderName) {
-    if (!this._imap) {
-      throw new IMAPConnectionNotReadyError(`IMAPBox::moveFromBox`)
-    }
-    return this._imap.moveAsync(range, folderName)
-  }
-
-  closeBox({expunge = true} = {}) {
-    if (!this._imap) {
-      throw new IMAPConnectionNotReadyError(`IMAPBox::closeBox`)
-    }
-    return this._imap.closeBoxAsync(expunge)
-  }
-}
-
+const IMAPBox = require('./imap-box');
+const {
+  IMAPConnectionNotReadyError,
+  IMAPConnectionEndedError,
+} = require('./imap-errors');
 
 const Capabilities = {
   Gmail: 'X-GM-EXT-1',
@@ -195,8 +45,9 @@ class IMAPConnection extends EventEmitter {
 
   connect() {
     if (!this._connectPromise) {
-      this._connectPromise = this._resolveIMAPSettings()
-      .then((settings) => this._buildUnderlyingConnection(settings))
+      this._connectPromise = this._resolveIMAPSettings().then((settings) =>
+        this._buildUnderlyingConnection(settings)
+      );
     }
     return this._connectPromise;
   }
@@ -237,16 +88,6 @@ class IMAPConnection extends EventEmitter {
     return new Promise((resolve, reject) => {
       this._imap = Promise.promisifyAll(new Imap(settings));
 
-      this._imap.once('end', () => {
-        this._logger.info('Underlying IMAP Connection ended');
-        this._connectPromise = null;
-        this._imap = null;
-      });
-
-      this._imap.on('alert', (msg) => {
-        this._logger.info({imap_server_msg: msg}, `IMAP server message`)
-      })
-
       // Emitted when new mail arrives in the currently open mailbox.
       // Fix https://github.com/mscdex/node-imap/issues/445
       let lastMailEventBox = null;
@@ -263,8 +104,26 @@ class IMAPConnection extends EventEmitter {
 
       // Emitted when message metadata (e.g. flags) changes externally.
       this._imap.on('update', () => this.emit('update'))
-      this._imap.once('ready', () => resolve(this));
-      this._imap.once('error', reject);
+
+      this._imap.once('ready', () => {
+        resolve(this)
+      });
+
+      this._imap.once('error', (err) => {
+        this.end();
+        reject(err);
+      });
+
+      this._imap.once('end', () => {
+        this._logger.info('Underlying IMAP Connection ended');
+        this._connectPromise = null;
+        this._imap = null;
+      });
+
+      this._imap.on('alert', (msg) => {
+        this._logger.info({imap_server_msg: msg}, `IMAP server message`)
+      });
+
       this._imap.connect();
     });
   }
@@ -293,7 +152,7 @@ class IMAPConnection extends EventEmitter {
       throw new IMAPConnectionNotReadyError(`IMAPConnection::openBox`)
     }
     return this._imap.openBoxAsync(folderName, readOnly).then((box) =>
-      new IMAPBox(this._imap, box)
+      new IMAPBox(this, box)
     )
   }
 
@@ -337,6 +196,45 @@ class IMAPConnection extends EventEmitter {
     });
   }
 
+  /*
+  Equivalent to new Promise, but allows you to easily create promises
+  which are also rejected when the IMAP connection is closed or ends.
+  This is important because node-imap sometimes just hangs the current
+  fetch / action forever after emitting an `end` event.
+  */
+  createConnectionPromise(callback) {
+    if (!this._imap) {
+      throw new IMAPConnectionNotReadyError(`IMAPConnection::createConnectionPromise`)
+    }
+
+    let onEnded = null;
+    let onErrored = null;
+
+    return new Promise((resolve, reject) => {
+      let returned = false;
+      onEnded = () => {
+        returned = true;
+        reject(new IMAPConnectionEndedError());
+      };
+      onErrored = (error) => {
+        returned = true;
+        reject(error || new Error("Unspecified IMAP error."));
+      };
+
+      this._imap.once('error', onEnded);
+      this._imap.once('end', onErrored);
+
+      const cresolve = (...args) => (!returned ? resolve(...args) : null)
+      const creject = (...args) => (!returned ? reject(...args) : null)
+      return callback(cresolve, creject)
+    }).finally(() => {
+      if (this._imap) {
+        this._imap.removeListener('error', onEnded);
+        this._imap.removeListener('end', onErrored);
+      }
+    });
+  }
+
   processNextOperation() {
     if (this._currentOperation) {
       return;
diff --git a/packages/nylas-core/imap-errors.js b/packages/nylas-core/imap-errors.js
new file mode 100644
index 000000000..3161deff5
--- /dev/null
+++ b/packages/nylas-core/imap-errors.js
@@ -0,0 +1,21 @@
+
+// "Source" is a hack so that the error matches the ones used by node-imap
+
+class IMAPConnectionNotReadyError extends Error {
+  constructor(funcName) {
+    super(`${funcName} - You must call connect() first.`);
+    this.source = 'socket';
+  }
+}
+
+class IMAPConnectionEndedError extends Error {
+  constructor(msg = "The IMAP Connection was ended.") {
+    super(msg);
+    this.source = 'socket';
+  }
+}
+
+module.exports = {
+  IMAPConnectionNotReadyError,
+  IMAPConnectionEndedError,
+};
diff --git a/packages/nylas-core/models/account/file.js b/packages/nylas-core/models/account/file.js
index 655e8b13d..ba52ed4d2 100644
--- a/packages/nylas-core/models/account/file.js
+++ b/packages/nylas-core/models/account/file.js
@@ -24,12 +24,9 @@ module.exports = (sequelize, Sequelize) => {
         .then(({message, connection}) => {
           return message.getFolder()
           .then((folder) => connection.openBox(folder.name))
-          .then((imapBox) => imapBox.fetchStream({
-            uid: message.folderImapUID,
-            options: {
-              bodies: [this.partId],
-              struct: true,
-            },
+          .then((imapBox) => imapBox.fetchMessageStream(message.folderImapUID, {
+            bodies: [this.partId],
+            struct: true,
           }))
           .then((stream) => {
             if (stream) {
diff --git a/packages/nylas-sync/imap/fetch-messages-in-folder.js b/packages/nylas-sync/imap/fetch-messages-in-folder.js
index 038dde66d..9ce3fe108 100644
--- a/packages/nylas-sync/imap/fetch-messages-in-folder.js
+++ b/packages/nylas-sync/imap/fetch-messages-in-folder.js
@@ -166,8 +166,7 @@ class FetchMessagesInFolder {
   _fetchMessagesAndQueueForProcessing(range) {
     const uidsByPart = {};
 
-    const $structs = this._box.fetch(range, {struct: true})
-    $structs.subscribe(({attributes}) => {
+    return this._box.fetchEach(range, {struct: true}, ({attributes}) => {
       const desiredParts = this._getDesiredMIMEParts(attributes.struct);
       if (desiredParts.length === 0) {
         return;
@@ -175,13 +174,13 @@ class FetchMessagesInFolder {
       const key = JSON.stringify(desiredParts);
       uidsByPart[key] = uidsByPart[key] || [];
       uidsByPart[key].push(attributes.uid);
-    });
-
-    return $structs.toPromise().then(() => {
+    })
+    .then(() => {
       return Promise.each(Object.keys(uidsByPart), (key) => {
         const uids = uidsByPart[key];
         const desiredParts = JSON.parse(key);
         const bodies = ['HEADER'].concat(desiredParts.map(p => p.id));
+
         this._logger.info({
           key,
           num_messages: uids.length,
@@ -190,17 +189,14 @@ class FetchMessagesInFolder {
         // note: the order of UIDs in the array doesn't matter, Gmail always
         // returns them in ascending (oldest => newest) order.
 
-        const $body = this._box.fetch(uids, {bodies, struct: true})
-        $body.subscribe((msg) => {
+        return this._box.fetchEach(uids, {bodies, struct: true}, (msg) => {
           msg.body = {};
           for (const {id, mimetype} of desiredParts) {
             msg.body[mimetype] = msg.parts[id];
           }
           this._processMessage(msg);
         });
-
-        return $body.toPromise();
-      })
+      });
     });
   }