Problems deploying printers

Question

Hi,
I've some bizarre problems when deploying printers, so I just hope you can give me few hints on where or what to check here.
We've one domain, 2 DC (older, physical dc is 2003 and vm one as 2008r2).
We've 2 print servers (2008R2) and a new one i'm creating from scratch, 2012R2.
Everything but the new 2012R2 print server was managed by external people so I basically have no idea of what's been done there, just have faith it's somehow working. 
Older print servers have about 150 printers each one, and we've hundeds of GPO in our DCs (we've more than 4000 client computers to control and about 40000 users in our DC, so it's not easy to make some steps/decisions).
Now, the problem (mainly noticed on the 2008 servers):
When I change to a GPO that deploys printers to our clients, operations such as adding a printer or changing a driver usually is 'Ok', but
sometimes seems like GPO aren't applied at all on clients. Spooler on clients start crashing (win7 clients show green progress bar and never show printers, win 8 crashes spooler process) and so on. Doing a gpupdate
says everything is ok, but changes aren't applied.
Funniest thing is when I try to remove a printer from deploying (for example, for problems with current driver on that printer). I remove it from GPO either from 'Deploy by group policy' context menu at printmanagement.msc, or editing printer connections
on GPO. No matter how I do this, seems like a local, cached copy of the GPO keeps in client computer, so I get printer even if removed, and later if I deploy it again, I get two or even tree copies of same printer! (or if I remove printer from server, clients
show me a ghost printer since it doesn't exists anymore!).
I believe this problem has been hanging for months or years, but not until now people has decided to start using print servers seriously and they were using printers locally, so the problem is now showing in full splendor.
Also, as last but not least, want to say that the way GPOs deploy printers is:
- Deploy printer per machine
- Same GPO is used for both older XP and new Win7 and Win8 clients, so GPO executes pushprinterconnections.
I was thinking in redoing all (over 150) printer deployment GPO using GPP instead, but while there are these problems (and where we still have XP) won't be able to do that, so any help would be appreciated.
Thanks

Answer 1

Hi Alan,
Will try these GPO, but according to the URL, I should put:
Execute Print Drivers in Isolated Processes = enabled (same as not configured)
Override Print Driver Execution Compatibility Setting Reported by Print Driver = disabled (again, same as not configured)
So, both options should be 'active'. I've made changes in server side (changed driver from shared or none to isolated, with no luck). Must I remove printer from deploy and later readd when I make an isolation change?
Anyway, on my Win8 testing box, I noticed there are printers still showing even GPO that put them there isn't active anymore. 
Found that there was a copy of GPO in
c:\windows\system32\grouppolicy\Datastore\0\sysvol\<domain name>\Policies
So I manually deleted shared printers, renamed folder inside Datastore from 0 to 1 to prevent old policies to execute, executed gpupdate /force (folder 0 was created again with a new copy of GPO), but again, old printers appeared there.
Did a registry search of ghost printer names, found them in:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Print\Providers\Client Side Rendering Print Provider\Servers\<SERVERNAME>\Monitors\Client Side Port\{043C1464-A566-4CB0-AFE7-24DC71DEF147}
And in 
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Print\Providers\Client Side Rendering Print Provider\Servers\<SERVERNAME>\Printers\{043C1464-A566-4CB0-AFE7-24DC71DEF147}
Also, found them duplicated in HKLM\Software\Wow6432Node\<blablabla>...
Not sure what {043C1464-A566-4CB0-AFE7-24DC71DEF147} is (doesn't resemble any GPO UID, but I could be a testing GPO I already deleted), nor sure why it's there or if it's safe to remove them from registry.
Hope this info gives any hint of why are them still there, problem with GPO, with print server, domain, or just client computer (altough there are more and more computers with this problem spanning).
As for the reason about not using user deployment, basically it's 'previous admins told us to keep doing this way as the did always'. Anyway, where we have this problem, that is, co-workers computers, there are one or at most 2 workers on every computer,
so made sense to put them on computer. Anyway, today I did several tests with GPP using per user on a new OU, and got mixed feelings. Liked the way it created, but disliked the fact that every few minutes (guess it was every time gpo was rechecked), default
printer was modified to local ones (guess that was because i didn't marked any printer as default one). But this isn't relevant either for this tread, so I'll investigate more (and hopefully won't have to post questions for it :-)
Thanks in advance