Knowledge base KB0230

Conflict with Cylance security tool: think-cell's automatic update fails


I have the security tool Cylance installed and think-cell's automatic update is failing. If I start PowerPoint or Excel after an Office update, think-cell tries to install a compatible version, but the update fails.

think-cell update fails

Depending on the Cylance settings, another notification may appear, mentioning that executing a .TMP file was blocked by Cylance:

blocked by Cylance


A possible temporary workaround can only be applied by your Cylance administrators. After allowing the hash of the current think-cell build, the automatic update can be installed. This is only a temporary workaround since we regularly provide new builds to always be compatible with the latest Microsoft 365 updates.


We were already in contact with Cylance support to discuss the issue in detail and are waiting on a solution. We have not yet been informed of a fix. If you want to contact Cylance to ask for a fix, you may refer to Cylance' engineering case #CHP-7436.


think-cell's automatic update usually makes sure you have the latest build with the latest improvements. If an update is available it will be downloaded and installed automatically in the background.

Depending on the installation context, it is downloaded into C:\Windows\Temp (per-machine installation) or %LOCALAPPDATA%\Temp (per-user installation) and executed from there.

According to the think-cell log files, the update is available and the download is started:

Request think-cell update from
Update request succeeded and update is available

However, if Cylance is available the installation fails with APIERR 5 Access is denied.:


Note: The .TMP file with the random file name is think-cell's .exe installer.

think-cell uses cookies to improve the functionality, performance and security of this site. Your consent is necessary if you want to use the full functionality of this site. More information on the use of cookies by think-cell, your consent and your privacy rights can be found in our privacy policy.