This issue can be caused if any of the following is true:

• The path where the TMP or TEMP environment variable points is unavailable or is read-only. For example, this issue occurs if the TMP environment variable is mapped to a remote drive or to a storage area network (SAN), and that mapped drive or SAN is no longer available.
  
  
• The TMP or TEMP environment variable has an incorrect registry setting.
  
  
• Exchange does not have full control permissions from the root of the drive down to the transaction logs and databases.
  
  

To resolve this issue, you can perform one or more of the following:

Note   Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see the product documentation to complete these steps.

• Verify that both the TMP environment variable and the TEMP environment variable point to a valid location in Windows. To do this, follow these steps:
  
  To set a valid path for the Temp and TMP variables

  1. Click Start, point to Settings, and then click Control Panel.

  2. Double-click System, click the Advanced tab, and then click Environment Variables.

  3. Under System variables, click TEMP, and then click Edit.

  4. If a valid path does not appear in the Variable Value box, type a valid path for the TEMP variable, and then click OK. For example, type %systemroot%\Temp, and then click OK.

  5. Under System variables, click TMP, and then click Edit.

  6. If a valid path does not appear in the Variable Value box, type a valid path for the TMP variable, and then click OK. For example, type %systemroot%\Temp, and then click OK.

  7. Click OK two times to close the System Properties dialog box.

  8. Restart the computer.

• Verify and assign the local Administrators group or the SYSTEM account Full Control permissions to the Temp folder. It is insufficient to assign Full Control permissions to the Domain Admins group. By default, the following path is specified for both the TMP and the TEMP system environment variables:
  
  %SYSTEMROOT%\Temp
  
  Exchange must access this folder location by using the SYSTEM account. To view these permissions follow these steps:
  
  To verify permissions to the Temp folder

  1. Right-click Start, and then click Explore.

  2. Right-click the Temp folder that is specified in the system environment variable, then click Properties. Typically, this is %systemroot%\Temp.

  3. Click the Security tab.

  4. In the Name list, click SYSTEM, and then view the assigned permissions that appear in the Permissions list.

  If permissions to the Temp folder are correct, verify the permissions on each drive that contains the Exchange database files or the Exchange log files. The SYSTEM account must have Full Control permissions at the root of the drive and at each folder that contains Exchange database files or the Exchange transaction log files. For example, if you have transaction logs in the C:\Exchsrvr\Mdbdata folder, the SYSTEM account must have Full Control permissions to the root directory of drive C, the Exchsrvr folder, and the Mdbdata folder.
  
  
• Check whether the problem is because of incorrect registry settings. Follow these steps:
  
  To verify registry settings

  1. Click Start, click Run, type Regedt32.exe, and then click OK.

  2. Locate the following registry key:

     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment

  3. Locate the TMP (or TEMP) name. This key should be of the REG_EXPAND_SZ type.

  4. If either of the keys is incorrect, back up the Environment subkey and then delete the TMP or TEMP value on the right.

  5. Click Start, click Run, type Sysdm.cpl, and then click OK.

  6. On the Advanced tab, click Environment Variables.

  7. In the System variables list, verify that the value(s) you deleted in step 4 is not present in the list.

     Note:
     You may have to scroll down to see the TEMP or TMP variables.

  8. Click New. In the Variable Name box, type the names that you deleted in step 4. For example, type C:\Winnt\TEMP.

  9. Click OK three times, and then restart the computer.