diff --git a/garden-service/src/commands/run/task.ts b/garden-service/src/commands/run/task.ts
index a1c81a46a9..af81f74dd0 100644
--- a/garden-service/src/commands/run/task.ts
+++ b/garden-service/src/commands/run/task.ts
@@ -51,7 +51,7 @@ export class RunTaskCommand extends Command<Args, Opts> {
 
   async action(
     { garden, log, headerLog, footerLog, args, opts }: CommandParams<Args, Opts>,
-  ): Promise<CommandResult<TaskResult>> {
+  ): Promise<CommandResult<TaskResult | null>> {
     const graph = await garden.getConfigGraph()
     const task = await graph.getTask(args.task)
 
@@ -62,7 +62,7 @@ export class RunTaskCommand extends Command<Args, Opts> {
     const taskTask = await TaskTask.factory({ garden, graph, task, log, force: true, forceBuild: opts["force-build"] })
     const result = (await garden.processTasks([taskTask]))[taskTask.getKey()]
 
-    if (!result.error) {
+    if (result && !result.error) {
       log.info("")
       // TODO: The command will need to be updated to stream logs: see https://github.com/garden-io/garden/issues/630.
       // It's ok with the current providers but the shape might change in the future.
diff --git a/garden-service/src/garden.ts b/garden-service/src/garden.ts
index 3a2cb85b8f..3dac9074da 100644
--- a/garden-service/src/garden.ts
+++ b/garden-service/src/garden.ts
@@ -499,14 +499,14 @@ export class Garden {
       const failed = Object.values(taskResults).filter(r => r && r.error)
 
       if (failed.length) {
-        const messages = failed.map(r => `- ${r.name}: ${r.error!.message}`)
+        const messages = failed.map(r => `- ${r!.name}: ${r!.error!.message}`)
         throw new PluginError(
           `Failed resolving one or more provider configurations:\n${messages.join("\n")}`,
           { rawConfigs, taskResults, messages },
         )
       }
 
-      const providers: Provider[] = Object.values(taskResults).map(result => result.output)
+      const providers: Provider[] = Object.values(taskResults).map(result => result!.output)
 
       await Bluebird.map(providers, async (provider) =>
         Bluebird.map(provider.moduleConfigs, async (moduleConfig) => {
diff --git a/garden-service/src/plugins/kubernetes/init.ts b/garden-service/src/plugins/kubernetes/init.ts
index bd8db58393..a143384a9f 100644
--- a/garden-service/src/plugins/kubernetes/init.ts
+++ b/garden-service/src/plugins/kubernetes/init.ts
@@ -153,7 +153,7 @@ export async function prepareSystem(
   }
 
   const serviceStatuses: ServiceStatusMap = (status.detail && status.detail.serviceStatuses) || {}
-  const serviceStates = Object.values(serviceStatuses).map(s => s.state!)
+  const serviceStates = Object.values(serviceStatuses).map(s => (s && s.state) || "unknown")
   const combinedState = combineStates(serviceStates)
 
   const remoteCluster = provider.name !== "local-kubernetes"
diff --git a/garden-service/src/plugins/kubernetes/status/service.ts b/garden-service/src/plugins/kubernetes/status/service.ts
index 1e442c0d5e..e34a807784 100644
--- a/garden-service/src/plugins/kubernetes/status/service.ts
+++ b/garden-service/src/plugins/kubernetes/status/service.ts
@@ -47,7 +47,7 @@ export async function waitForServiceEndpoints(
     while (true) {
       const endpoints = await api.core.readNamespacedEndpoints(serviceName, serviceNamespace)
 
-      const addresses = flatten(endpoints.subsets!.map(subset => subset.addresses || []))
+      const addresses = flatten((endpoints.subsets || []).map(subset => subset.addresses || []))
       const routedPods = addresses
         .filter(a => a.targetRef!.kind === "Pod" && readyPodNames.includes(a.targetRef!.name!))
 
diff --git a/garden-service/src/plugins/kubernetes/system.ts b/garden-service/src/plugins/kubernetes/system.ts
index cd298836ac..2e58cb4040 100644
--- a/garden-service/src/plugins/kubernetes/system.ts
+++ b/garden-service/src/plugins/kubernetes/system.ts
@@ -150,7 +150,7 @@ export async function getSystemServiceStatus(
   const actions = await sysGarden.getActionHelper()
 
   const serviceStatuses = await actions.getServiceStatuses({ log, serviceNames })
-  const state = combineStates(values(serviceStatuses).map(s => s.state || "unknown"))
+  const state = combineStates(values(serviceStatuses).map(s => (s && s.state) || "unknown"))
 
   // Add the Kubernetes dashboard to the Garden dashboard
   if (serviceNames.includes("kubernetes-dashboard")) {
diff --git a/garden-service/src/task-graph.ts b/garden-service/src/task-graph.ts
index f84bbe8657..da56d0bd91 100644
--- a/garden-service/src/task-graph.ts
+++ b/garden-service/src/task-graph.ts
@@ -37,7 +37,7 @@ export interface TaskResult {
  * the result from the last processed is used (hence only one key-value pair here per key).
  */
 export interface TaskResults {
-  [key: string]: TaskResult
+  [key: string]: TaskResult | null
 }
 
 const DEFAULT_CONCURRENCY = 6
diff --git a/garden-service/src/tasks/base.ts b/garden-service/src/tasks/base.ts
index 2ed85d955b..7dbc0c4cff 100644
--- a/garden-service/src/tasks/base.ts
+++ b/garden-service/src/tasks/base.ts
@@ -79,19 +79,19 @@ export abstract class BaseTask {
 }
 
 export function getServiceStatuses(dependencyResults: TaskResults): { [name: string]: ServiceStatus } {
-  const getServiceStatusResults = pickBy(dependencyResults, r => r.type === "get-service-status")
-  const deployResults = pickBy(dependencyResults, r => r.type === "deploy")
+  const getServiceStatusResults = pickBy(dependencyResults, r => r && r.type === "get-service-status")
+  const deployResults = pickBy(dependencyResults, r => r && r.type === "deploy")
   // DeployTask results take precedence over GetServiceStatusTask results, because status changes after deployment
   const combined = { ...getServiceStatusResults, ...deployResults }
-  const statuses = mapValues(combined, r => r.output as ServiceStatus)
+  const statuses = mapValues(combined, r => r!.output as ServiceStatus)
   return mapKeys(statuses, (_, key) => splitLast(key, ".")[1])
 }
 
 export function getRunTaskResults(dependencyResults: TaskResults): { [name: string]: RunTaskResult } {
-  const storedResults = pickBy(dependencyResults, r => r.type === "get-task-result")
-  const runResults = pickBy(dependencyResults, r => r.type === "task")
+  const storedResults = pickBy(dependencyResults, r => r && r.type === "get-task-result")
+  const runResults = pickBy(dependencyResults, r => r && r.type === "task")
   // TaskTask results take precedence over GetTaskResultTask results
   const combined = { ...storedResults, ...runResults }
-  const results = mapValues(combined, r => r.output as RunTaskResult)
+  const results = mapValues(combined, r => r!.output as RunTaskResult)
   return mapKeys(results, (_, key) => splitLast(key, ".")[1])
 }
diff --git a/garden-service/src/tasks/resolve-provider.ts b/garden-service/src/tasks/resolve-provider.ts
index 0a154f8cf7..9d7eca89bf 100644
--- a/garden-service/src/tasks/resolve-provider.ts
+++ b/garden-service/src/tasks/resolve-provider.ts
@@ -81,7 +81,7 @@ export class ResolveProviderTask extends BaseTask {
   }
 
   async process(dependencyResults: TaskResults) {
-    const resolvedProviders: Provider[] = Object.values(dependencyResults).map(result => result.output)
+    const resolvedProviders: Provider[] = Object.values(dependencyResults).map(result => result && result.output)
 
     const context = new ProviderConfigContext(this.garden.environmentName, this.garden.projectName, resolvedProviders)
 
diff --git a/garden-service/test/helpers.ts b/garden-service/test/helpers.ts
index 2492aa9bfe..167cd0e310 100644
--- a/garden-service/test/helpers.ts
+++ b/garden-service/test/helpers.ts
@@ -386,7 +386,7 @@ export async function expectError(fn: Function, typeOrCallback?: string | ((err:
 }
 
 export function taskResultOutputs(results: TaskResults) {
-  return mapValues(results, r => r.output)
+  return mapValues(results, r => r && r.output)
 }
 
 export const cleanProject = async (gardenDirPath: string) => {
diff --git a/garden-service/test/unit/src/plugins/exec.ts b/garden-service/test/unit/src/plugins/exec.ts
index 4f92d62ede..4daa62e4bf 100644
--- a/garden-service/test/unit/src/plugins/exec.ts
+++ b/garden-service/test/unit/src/plugins/exec.ts
@@ -149,7 +149,7 @@ describe("exec plugin", () => {
     const results = await _garden.processTasks([taskTask])
 
     // Task A echoes "task-a-output" and Task B echoes the output from Task A
-    expect(results["task.task-b"].output.outputs.log).to.equal("task-a-output")
+    expect(results["task.task-b"]!.output.outputs.log).to.equal("task-a-output")
   })
 
   describe("getBuildStatus", () => {
diff --git a/garden-service/test/unit/src/plugins/terraform/terraform.ts b/garden-service/test/unit/src/plugins/terraform/terraform.ts
index e0336100ad..098d42264b 100644
--- a/garden-service/test/unit/src/plugins/terraform/terraform.ts
+++ b/garden-service/test/unit/src/plugins/terraform/terraform.ts
@@ -90,6 +90,6 @@ describe("Terraform module type", () => {
 
   it("should expose runtime outputs to template contexts", async () => {
     const result = await runTestTask()
-    expect(result["task.test-task"].output.outputs.log).to.equal("input: foo")
+    expect(result["task.test-task"]!.output.outputs.log).to.equal("input: foo")
   })
 })