diff --git a/src/connect.ts b/src/connect.ts
index 00b8d2c..be40923 100644
--- a/src/connect.ts
+++ b/src/connect.ts
@@ -147,6 +147,10 @@ export async function createSocket(config: FileSystemConfig): Promise<NodeJS.Rea
           Logging.debug(`\tError connecting to hop ${config.hop} for ${config.name}: ${err}`);
           err.message = `Couldn't connect through the hop:\n${err.message}`;
           return reject(err);
+        } else if (!channel) {
+          err = new Error('Did not receive a channel');
+          Logging.debug(`\tGot no channel when connecting to hop ${config.hop} for ${config.name}`);
+          return reject(err);
         }
         channel.once('close', () => ssh.destroy());
         resolve(channel);
@@ -159,9 +163,9 @@ export async function createSocket(config: FileSystemConfig): Promise<NodeJS.Rea
       break;
     case 'socks4':
     case 'socks5':
-      return await (await import ('./proxy')).socks(config);
+      return await (await import('./proxy')).socks(config);
     case 'http':
-      return await (await import ('./proxy')).http(config);
+      return await (await import('./proxy')).http(config);
     default:
       throw new Error(`Unknown proxy method`);
   }
diff --git a/src/sshFileSystem.ts b/src/sshFileSystem.ts
index bc178a6..dfbb4b9 100644
--- a/src/sshFileSystem.ts
+++ b/src/sshFileSystem.ts
@@ -26,7 +26,7 @@ export class SSHFileSystem implements vscode.FileSystemProvider {
     if (relPath.startsWith('/')) relPath = relPath.substr(1);
     return path.posix.resolve(this.root, relPath);
   }
-  public continuePromise<T>(func: (cb: (err: Error | null, res?: T) => void) => boolean): Promise<T> {
+  public continuePromise<T>(func: (cb: (err: Error | null | undefined, res?: T) => void) => boolean): Promise<T> {
     return new Promise<T>((resolve, reject) => {
       const exec = () => {
         this.waitForContinue = false;
diff --git a/src/toPromise.ts b/src/toPromise.ts
index b2f84d7..5e2ba58 100644
--- a/src/toPromise.ts
+++ b/src/toPromise.ts
@@ -1,5 +1,5 @@
 
-export type toPromiseCallback<T> = (err: Error | null, res?: T) => void;
+export type toPromiseCallback<T> = (err: Error | null | undefined, res?: T) => void;
 export async function toPromise<T>(func: (cb: toPromiseCallback<T>) => void): Promise<T> {
   return new Promise<T>((resolve, reject) => {
     try {
diff --git a/webview/src/FieldTypes/base.tsx b/webview/src/FieldTypes/base.tsx
index 79b0d3b..885b90a 100644
--- a/webview/src/FieldTypes/base.tsx
+++ b/webview/src/FieldTypes/base.tsx
@@ -50,7 +50,7 @@ export abstract class FieldBase<T, P = {}, S = {}> extends React.Component<Props
         }
         return validator ? validator(newValue!) : null;
     }
-    public getValue(): T {
+    public getValue(): T | undefined {
         const { newValue, oldValue } = this.state;
         if (newValue === undefined) {
             return this.props.optional ? newValue : oldValue;
diff --git a/webview/src/FieldTypes/dropdown.tsx b/webview/src/FieldTypes/dropdown.tsx
index 61e119d..648840d 100644
--- a/webview/src/FieldTypes/dropdown.tsx
+++ b/webview/src/FieldTypes/dropdown.tsx
@@ -23,7 +23,7 @@ export class FieldDropdown<T> extends FieldBase<T, Props<T>, State<T>> {
     public renderInput() {
         const { newValue, open } = this.state;
         const { displayName } = this.props;
-        const display = newValue ? (displayName ? displayName(newValue) : newValue.toString()) : '';
+        const display = newValue ? (displayName ? displayName(newValue) : `${newValue}`) : '';
         return <div className="FieldDropdown" ref={this.mainDivRef}>
             <p style={{ float: 'right', margin: 5 }}>▼</p>
             <div className="current" onClick={this.toggle}>{display}</div>
@@ -35,7 +35,7 @@ export class FieldDropdown<T> extends FieldBase<T, Props<T>, State<T>> {
         const generateItem = (item: T, index: number) => {
             const style = displayStyle && displayStyle(item);
             return <li key={index} style={style} onClick={this.select.bind(this, item)}>
-                {displayName ? displayName(item) : item.toString()}
+                {displayName ? displayName(item) : `${item}`}
             </li>
         };
         return <ul className="list">