diff --git a/Common/Controllers/ColorBars.swift b/Common/Controllers/ColorBars.swift
new file mode 100644
index 0000000..b4e3ae9
--- /dev/null
+++ b/Common/Controllers/ColorBars.swift
@@ -0,0 +1,77 @@
+//
+//  ColorBars.swift
+//  NewTerm Common
+//
+//  Created by Adam Demasi on 23/9/21.
+//
+
+import Foundation
+
+struct ColorBars {
+
+	private struct RGB: CustomStringConvertible {
+		var r: Int, g: Int, b: Int
+
+		init(_ r: Int, _ g: Int, _ b: Int) {
+			self.r = r
+			self.g = g
+			self.b = b
+		}
+
+		var description: String { "\(r);\(g);\(b)" }
+	}
+
+	private static let bars: [[RGB]] = [
+		[RGB(192, 192, 192), RGB(192, 192,   0), RGB( 0, 192, 192), RGB(  0, 192,   0), RGB(192,   0, 192), RGB(192,   0,   0), RGB(  0,   0, 192)],
+		[RGB(  0,   0, 192), RGB( 19,  19,  19), RGB(192,  0, 192), RGB( 19,  19,  19), RGB(  0, 192, 192), RGB( 19,  19,  19), RGB(192, 192, 192)],
+		[RGB(  0,  33,  76), RGB(255, 255, 255), RGB( 50,  0, 106), RGB( 19,  19,  19), RGB(  9,   9,   9), RGB( 19,  19,  19), RGB( 29,  29,  29), RGB( 19,  19,  19)]
+	]
+
+	static func render(screenSize: ScreenSize, message: String) -> Data {
+		// Don’t bother drawing if the screen is too small
+		if screenSize.cols < 7 || screenSize.rows < 10 {
+			return Data()
+		}
+
+		// Draw color bars
+		let firstSectionSize = ScreenSize(cols: UInt(Double(screenSize.cols) / 7),
+																			rows: UInt(Double(screenSize.rows) * 0.66))
+		let thirdSectionSize = ScreenSize(cols: UInt(Double(screenSize.cols) / 6),
+																			rows: UInt(Double(screenSize.rows) * 0.25))
+		let secondSectionSize = ScreenSize(cols: UInt(Double(screenSize.cols) / 7),
+																			 rows: screenSize.rows - firstSectionSize.rows - thirdSectionSize.rows - 1)
+		var data = "\u{1b}c".data(using: .utf8)!
+		let space = String(repeating: " ", count: Int(firstSectionSize.cols))
+		for _ in 0..<firstSectionSize.rows {
+			for color in bars[0] {
+				data.append("\u{1b}[48;2;\(color)m\(space)".data(using: .utf8)!)
+			}
+			data.append("\u{1b}[0m\r\n".data(using: .utf8)!)
+		}
+		for _ in 0..<secondSectionSize.rows {
+			for color in bars[1] {
+				data.append("\u{1b}[48;2;\(color)m\(space)".data(using: .utf8)!)
+			}
+			data.append("\u{1b}[0m\r\n".data(using: .utf8)!)
+		}
+		let finalSpace = String(repeating: " ", count: Int(thirdSectionSize.cols))
+		let finalInnerWidth = Int(Double(thirdSectionSize.cols) / 3)
+		let finalInnerSpace = String(repeating: " ", count: finalInnerWidth)
+		for _ in 0..<thirdSectionSize.rows {
+			for i in 0..<bars[2].count {
+				// Special case: There is a gradient of 3 colors in the second-last rectangle.
+				let space = i >= 4 && i <= 6 ? finalInnerSpace : finalSpace
+				data.append("\u{1b}[48;2;\(bars[2][i])m\(space)".data(using: .utf8)!)
+			}
+			data.append("\u{1b}[0m\r\n".data(using: .utf8)!)
+		}
+
+		// Draw error text
+		let textPosition = ScreenSize(cols: UInt(max(0, Double((Int(firstSectionSize.cols * 7) - message.count + 2) / 2).rounded(.toNearestOrEven))),
+																	rows: UInt(Double(screenSize.rows / 2).rounded(.down)))
+		data.append("\u{1b}[\(textPosition.rows);\(textPosition.cols)H\u{1b}[1;7m \(message) \u{1b}[m\u{1b}[\(screenSize.cols);0H".data(using: .utf8)!)
+
+		return data
+	}
+
+}
diff --git a/Common/Controllers/SubProcess.swift b/Common/Controllers/SubProcess.swift
index 859ce5d..1ae0fdb 100644
--- a/Common/Controllers/SubProcess.swift
+++ b/Common/Controllers/SubProcess.swift
@@ -11,7 +11,7 @@ import os.log
 
 enum SubProcessIllegalStateError: Error {
 	case alreadyStarted, notStarted
-	case openPtyFailed, forkFailed, inSandbox
+	case openPtyFailed, forkFailed(errno: Int32)
 	case deallocatedWhileRunning
 }
 
@@ -64,12 +64,9 @@ class SubProcess: NSObject {
 		switch pid {
 		case -1:
 			// Fork failed.
-			os_log("Fork failed: %{public errno}d", type: .error, errno)
-			if errno == EPERM {
-				throw SubProcessIllegalStateError.inSandbox
-			} else {
-				throw SubProcessIllegalStateError.forkFailed
-			}
+			let error = errno
+			os_log("Fork failed: %{public errno}d", type: .error, error)
+			throw SubProcessIllegalStateError.forkFailed(errno: error)
 
 		case 0:
 			// We’re in the fork. Execute the login shell.
@@ -99,8 +96,9 @@ class SubProcess: NSObject {
 			}
 
 			if execve(path, args, env) == -1 {
-				os_log("%{public}@: exec failed: %{public errno}d", type: .error, path, errno)
-				throw SubProcessIllegalStateError.forkFailed
+				let error = errno
+				os_log("%{public}@: exec failed: %{public errno}d", type: .error, path, error)
+				throw SubProcessIllegalStateError.forkFailed(errno: error)
 			}
 			break
 
diff --git a/Common/Controllers/TerminalController.swift b/Common/Controllers/TerminalController.swift
index 4eab1d5..06cb960 100644
--- a/Common/Controllers/TerminalController.swift
+++ b/Common/Controllers/TerminalController.swift
@@ -43,6 +43,7 @@ public class TerminalController {
 
 	internal var terminal: Terminal?
 	private var subProcess: SubProcess?
+	private var subProcessFailureErrno: Int32?
 	private let stringSupplier = StringSupplier()
 
 	private var processLaunchDate: Date?
@@ -171,7 +172,16 @@ public class TerminalController {
 		subProcess = SubProcess()
 		subProcess!.delegate = self
 		processLaunchDate = Date()
-		try subProcess!.start()
+		do {
+			try subProcess!.start()
+		} catch {
+			if case SubProcessIllegalStateError.forkFailed(let forkError) = error {
+				subProcessFailureErrno = forkError
+			} else {
+				subProcessFailureErrno = -1
+			}
+			throw error
+		}
 	}
 
 	public func stopSubProcess() throws {
@@ -222,6 +232,11 @@ public class TerminalController {
 			subProcess?.screenSize = screenSize
 			terminal.resize(cols: Int(screenSize.cols),
 											rows: Int(screenSize.rows))
+
+			if let error = subProcessFailureErrno {
+				let message = String(utf8String: strerror(error)) ?? "Error"
+				readInputStream(ColorBars.render(screenSize: screenSize, message: message))
+			}
 		}
 	}
 
diff --git a/NewTerm.xcodeproj/project.pbxproj b/NewTerm.xcodeproj/project.pbxproj
index a86c5c2..412e901 100644
--- a/NewTerm.xcodeproj/project.pbxproj
+++ b/NewTerm.xcodeproj/project.pbxproj
@@ -14,6 +14,7 @@
 		4E2492D026230E59002C47CB /* TerminalController+ITermExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4E2492CF26230E59002C47CB /* TerminalController+ITermExtensions.swift */; };
 		4E32378F26FB2D4400AEDA06 /* UIApplication+Additions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4E32378E26FB2D4400AEDA06 /* UIApplication+Additions.swift */; };
 		4E32379026FB4B3300AEDA06 /* String+Localization.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4E98081926184A2500E41883 /* String+Localization.swift */; };
+		4E3237FB26FC5FC300AEDA06 /* ColorBars.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4E3237FA26FC5FC300AEDA06 /* ColorBars.swift */; };
 		4E460121261EC8C0004DBCC2 /* UpdateCheckManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4E460120261EC8C0004DBCC2 /* UpdateCheckManager.swift */; };
 		4E460129261FF23F004DBCC2 /* SettingsSceneDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4E460128261FF23F004DBCC2 /* SettingsSceneDelegate.swift */; };
 		4E479710262D44D8003CF48C /* Localizable.stringsdict in Resources */ = {isa = PBXBuildFile; fileRef = 4E479713262D44D8003CF48C /* Localizable.stringsdict */; };
@@ -123,6 +124,7 @@
 		4E0A97A32685D1CD0022F569 /* SettingsAcknowledgementsTextView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SettingsAcknowledgementsTextView.swift; sourceTree = "<group>"; };
 		4E2492CF26230E59002C47CB /* TerminalController+ITermExtensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "TerminalController+ITermExtensions.swift"; sourceTree = "<group>"; };
 		4E32378E26FB2D4400AEDA06 /* UIApplication+Additions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UIApplication+Additions.swift"; sourceTree = "<group>"; };
+		4E3237FA26FC5FC300AEDA06 /* ColorBars.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ColorBars.swift; sourceTree = "<group>"; };
 		4E460120261EC8C0004DBCC2 /* UpdateCheckManager.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UpdateCheckManager.swift; sourceTree = "<group>"; };
 		4E460128261FF23F004DBCC2 /* SettingsSceneDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SettingsSceneDelegate.swift; sourceTree = "<group>"; };
 		4E479712262D44D8003CF48C /* en */ = {isa = PBXFileReference; lastKnownFileType = text.plist.stringsdict; name = en; path = en.lproj/Localizable.stringsdict; sourceTree = "<group>"; };
@@ -312,6 +314,7 @@
 				CFBB96C222B5481B00585BE6 /* SubProcess.swift */,
 				CFBB96C522B5481B00585BE6 /* TerminalController.swift */,
 				4E2492CF26230E59002C47CB /* TerminalController+ITermExtensions.swift */,
+				4E3237FA26FC5FC300AEDA06 /* ColorBars.swift */,
 			);
 			path = Controllers;
 			sourceTree = "<group>";
@@ -718,6 +721,7 @@
 				4E9FB97226172079005AFCC8 /* Color+Additions.swift in Sources */,
 				CF71BCDE22BB73C200AFB1E1 /* Global.swift in Sources */,
 				CF71BCA822BB6E1100AFB1E1 /* NSLayoutConstraint+CompactConstraint.m in Sources */,
+				4E3237FB26FC5FC300AEDA06 /* ColorBars.swift in Sources */,
 				CF71BCA922BB6E1100AFB1E1 /* UIView+CompactConstraint.m in Sources */,
 				CF71BCF122BB8AAB00AFB1E1 /* FontMetrics.swift in Sources */,
 				CF71BC9722BB6E0300AFB1E1 /* Preferences.swift in Sources */,
diff --git a/Resources/en.lproj/Localizable.strings b/Resources/en.lproj/Localizable.strings
index f09d3bb..08d46dd 100644
--- a/Resources/en.lproj/Localizable.strings
+++ b/Resources/en.lproj/Localizable.strings
@@ -22,6 +22,10 @@
 	<key>PASSWORD_MANAGER</key>
 	<string>Password Manager</string>
 
+	<!-- Message displayed in the terminal when it fails to start. -->
+	<key>TERMINAL_LAUNCH_FAILED</key>
+	<string>The shell process quit unexpectedly.</string>
+
 	<!-- Alert title displayed when a terminal could not be launched. -->
 	<key>TERMINAL_LAUNCH_FAILED_TITLE</key>
 	<string>Couldn’t start the terminal because the shell process quit unexpectedly.</string>