AltStore and AltServer Errors: “Could Not Find AltServer” and Other Fixes (2026)

ByScarlet iOS Team Updated on

AltStore Classic installs apps with your own Apple Account and refreshes them through AltServer, a helper app on your Windows PC or Mac. Most AltStore errors are really connection problems between the iPhone and that computer. This guide explains the common messages and codes, using AltStore’s own error list and troubleshooting guide. Last checked: October 28, 2026.

This page is about AltStore Classic. AltStore PAL, the EU marketplace version, does not use AltServer: see the AltStore PAL guide.

Quick Table: Message, Cause, Fix

Message or code Cause First fix
1200 “AltServer could not be found” / “Could not find AltServer” AltStore cannot see AltServer on the network Same Wi-Fi as the computer, or connect by USB
1201 “A connection to AltServer could not be established” AltServer found but not reachable Turn on Wi-Fi sync, or connect by USB
1202 “The connection to AltServer was dropped” The connection broke during the action Wi-Fi sync on, or USB, then retry
2001 “There was an error connecting to the device” AltServer cannot talk to the iPhone Plug the iPhone into the computer
2002 “Lost Connection to AltServer” Connection dropped between AltServer and the iPhone Same Wi-Fi network, retry
2003 “AltServer could not find this device” Device not found over USB or Wi-Fi Same Wi-Fi, device trusted, retry
2004 “Failed to write app data to device” Writing the app was interrupted Same Wi-Fi, device trusted, retry
2005, 2006, 2011, 2012 invalid or unknown request/response AltStore or AltServer is outdated Update both to the latest version
2007 “The app is invalid” The IPA is not in a valid format Download it from another source
2008 “An error occurred while installing the app” iOS rejected the app Use a version made for your iOS
2009 “Cannot activate more than 3 apps” Free Apple Account app limit Deactivate an app
“[Device] is currently locked” The iPhone is locked Unlock it with your passcode and retry

“Could Not Find AltServer” (1200) and Connection Errors

AltStore says AltServer “must be running on a computer connected to the same WiFi as AltStore in order to sideload or refresh apps.” If both are on the same network and you still get the error, AltStore’s own checklist is:

  1. Public, work or school Wi-Fi often stops devices from finding each other. AltStore suggests connecting the computer to your phone’s hotspot instead.
  2. Trust on both sides. Connect the iPhone to the computer and check that you tapped Trust on the iPhone and allowed it on the computer (Finder on macOS 10.15 or later, iTunes on older macOS and on Windows).
  3. Windows firewall. Allow network access for AltServer, or it cannot receive refreshes from AltStore.
  4. Windows iTunes and iCloud. If they came from the Microsoft Store, uninstall them and install the versions downloaded directly from Apple. Keep iTunes and iCloud running while you use AltServer.
  5. USB. AltStore says plugging the iPhone into the computer “should fix all connectivity problems”, though background refresh over Wi-Fi may then not work.

For 1201 and 1202, AltStore adds: make sure Wi-Fi sync is enabled for the iPhone in Finder or iTunes. The same Windows iTunes advice applies to Sideloadly; see our Sideloadly guide.

AltServer Cannot Find or Write to the Device (2001 to 2004)

These come from AltServer itself. AltStore’s advice is the same for all of them: plug the iPhone directly into the computer, make sure both are on the same Wi-Fi network and the device is trusted, then try again. Unlock the iPhone first; AltStore stops with a “currently locked” message when it is locked.

Sign-In Freezes or Takes Forever

AltStore lists the same causes as for connection errors: restrictive Wi-Fi, a missing Trust, the Windows firewall, Microsoft Store versions of iTunes or iCloud, or iTunes and iCloud not running. It also suggests trying another Apple Account; you can make a free one just for sideloading.

Windows “vector too long” (Exception Error 0)

AltStore says this means Windows Defender is blocking the request, and that you may need to turn off Real-Time Protection for AltStore to work. If you do, turn it back on as soon as the install is done.

App and Version Errors

  • 2007 The app is invalid: the IPA is damaged or not a real IPA. Download it again from a source you trust, and check it: see how to scan IPA files for malware.
  • 2008 An error occurred while installing the app: AltStore says iOS rejected the app and to use a version compatible with your iOS. If the app needs a newer iOS, see how to fix “requires a newer version of iOS”.
  • 2010 Must be running iOS 12.2 or later: AltStore Classic needs at least iOS 12.2.

The 3-App Limit (2009)

AltStore says that “due to Apple’s restrictions only 3 sideloaded apps can be active at a time”. To free a slot, deactivate an app in AltStore: it backs up the app’s data and removes the app, and Activate later reinstalls it with its data. AltStore’s message adds a detail many people miss: on iOS 13.5 and later, turn off Offload Unused Apps and install or delete any offloaded apps, because they can still count toward the limit. Our 3-app limit guide covers every fix; a paid Apple Developer Program membership removes the limit.

JIT Could Not Be Enabled

AltStore’s first check is that the app is open in the foreground on the iPhone. After that, the same network, Trust and firewall steps apply.

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