Photoshop Looping Activation - Keeps asking for serial number

[Phil_Laz]

Hi,

I have PS CS5.1. All of a sudden, one day, when opening photoshop it randomly asked me for my serial number. I put this in and clicked the button to move to the next step (cannot remember what the button said). The dialog box then closed and it appeared that all was well again, but then it reloaded the very same dialog box, which once again asked for my serial number. I tried it a few more times and it kept looping and asking for the serial repeatedly. I then uninstalled photoshop and rebooted computer. Once rebooted I reinstalled. All looked to be well, but then when I attempt to open photoshop it again asks me for my serial. Again I have tried several times inputting the serial, but it just keeps asking. Aparently my 'Adobe Photoshop CS5.1 Trial has expired... It never was a trial version... I have now removed and installed several times. I have attempted to download adobe update manager. This appears to be installed, but nothing seems to update. I am now at a dead end and do not know what to try or how to resolve the issue. I have searched the net and cannot find any way to fix the problem. Any help will be greatly appreciated.

Regards.

The below image shows what I keep getting looped back to, no matter what I do.

[Mylenium]

Refer to this:

Sign in or activation errors

And check your system. Something is simply preventing the activation from being written to disk or the licensing service connecting to Adobe like a virus scanner or other security tool/ setting.

Mylenium

[Phil_Laz]

Hi,

Thank you very much for your attempt in helping. I have read through the link you gave. Nothing is of assistance there. (it doesnt get to activation). As soon as I press the continue button (second image) (after inputting serial codes (I have CS5 upgrade from 4, so need to put 2 serials in) it just loops straight back to the licesnse agreement (first image). I cannot get no further.

[Plastic743]

The link Milenium gave you there is also also a button to chat with a agent under "stil having problems
"

[Phil_Laz]

The problem was that something had cached that shouldn't have. The fix was renaming cache.db to cacheold.db (rather than just deleting in case it wasnt the problem) from the below location (Windows 8). C:\Program Files (x86)\Common Files\Adobe\Adobe PCD\cache

[Guest]

This did the trick for me!