Summary

Symptoms

When running an installation authored with InstallShield, the following error may occur:

Error 1500. Another installation is in progress. You must complete that installation before continuing this one.

Cause

When the Windows Installer performs a transaction, it adds a registry key called InProgress, which is located at HKEY_Local_Machine\Software\Microsoft\Windows\Installer\InProgress. When the transaction is done, it removes the key. Other installations check for this key before they begin. If the key exists, the installation does not start and produces Error 1500.

Possible Causes

1. Msiexec.exe has been launched via a custom action in the Execute sequence in an InstallShield installation. This causes more than one instance of Msiexec to be run at the same time. More than one instance of Msiexec cannot be run in the execute sequence.

2. In some cases, the InProgress key can be left behind if an installation is cancelled forcibly via the Task Manager during a transaction.

3. There is a mutex called _MsiExecute that prevents an installation from running. Sometimes other processes hold it. One such process is a MS Office service called the Office Web Server Notification Service (owstimer.exe) that may hold on to the _MsiExecute object, causing installations to be locked out.

Resolution

1. The custom action must be moved to the UI Sequence. Follow these steps to move the custom action.
   1. Open the Sequences view.
   2. Expand the Execute sequence of the appropriate sequencing folder. In most cases, this is the Installation sequencing folder.
   3. Within the Execute sequence find the custom action, right-click it, and choose delete or remove. If you are not sure which custom action to delete or remove, open the Custom Actions view and analyze the setting for any custom actions that you have added. The Filename & Command line property for the custom action should be set to MsiExec.exe. Once you find this action, delete or remove it from the Sequences view. Make sure NOT to delete or remove the action from the Custom Actions view.
   4. Open the User Interface sequence within the Installation folder.
   5. Right-click the action you wish the custom action to come after and select Insert.
   6. In the Insert Action dialog, choose custom action from the drop-down box list.
   7. Select the custom action and choose OK.

2. To remove the InProgress key, first try rebooting. If this does not work, download the Windows Installer SDK. There is a tool that comes with it called MsiZap.exe. This utility can be used, following its documentation, to remove the In-Progress key.

3. To find out whether or not a process is holding _MsiExecute, obtain a tool that allows you to view handles and processes, such as Handle v3.20, and search for _MsiExecute, then take steps to stop that process. Handle v3.51 is a free tool available at Sysinternals. Information on how to use this utility is provided on the download site.

   Note: If owstimer.exe is found in the Task Manager, set the service to start manually (it starts automatically by default) in the Service Control Manager, then reboot. On WinNT systems, the Service Control Manager is accessible via the Control panel. On Window 2000 systems, the Service Control Manager is accessible via the Administrative Tools section, which is accessible via the Control Panel.

Additional Information

Error 1500 is documented in the Windows Installer Help Library topic Windows Installer Error Messages.