Имя журнала: Microsoft-Windows-PrintService/Admin
Источник: Microsoft-Windows-PrintService
Дата: 24.04.2018 8:03:42
Код события: 808
Категория задачи:Инициализация
Уровень: Ошибка
Ключевые слова:Очередь печати принтера
Пользователь: QWERTY1\Иван
Компьютер: QWERTY1
Описание:
Очереди печати принтера не удается загрузить подключаемый модуль C:\Windows\system32\spool\DRIVERS\x64\3\UNIDRVUI.DLL, код ошибки 0xc1. Для получения сведений о контексте см. пользовательские данные события.
Xml события:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Microsoft-Windows-PrintService" Guid="{747EF6FD-E535-4D16-B510-42C90F6873A1}" />
<EventID>808</EventID>
<Version>0</Version>
<Level>2</Level>
<Task>36</Task>
<Opcode>12</Opcode>
<Keywords>0x8000000000020000</Keywords>
<TimeCreated SystemTime="2018-04-24T05:03:42.848102400Z" />
<EventRecordID>830</EventRecordID>
<Correlation />
<Execution ProcessID="3120" ThreadID="3012" />
<Channel>Microsoft-Windows-PrintService/Admin</Channel>
<Computer>QWERTY1</Computer>
<Security UserID="S-1-5-21-208439106-2742066226-3157559274-1000" />
</System>
<UserData>
<LoadPluginFailed xmlns:auto-ns3="http://schemas.microsoft.com/win/2004/08/events" xmlns="http://manifests.microsoft.com/win/2005/08/windows/printing/spooler/core/events">
<PluginDllName>C:\Windows\system32\spool\DRIVERS\x64\3\UNIDRVUI.DLL</PluginDllName>
<ErrorCode>0xc1</ErrorCode>
<Context>112</Context>
</LoadPluginFailed>
</UserData>
</Event>

I had the same problem (except with a different dll, PS5UI.dll). I am not sure what the significant of the ./3 directory in path was, as C:\windows\system32\spool\drivers\x64 seems to contain similar DLLs. What fixed it for me was this (I will keep it basic).
-First off, make sure you are on an admin account (if not, talk to your computer's administrator)
-Navigate to C:\Windows\System32
- In the search bar, type in your DLL name
(for me, it was again PS5UI.dll, for you probably "unidrvui.dll")
-If you are lucky, you should have results, mine were:
One copy with size 828 KB
C:\Windows\System32\DriverStore\FileRepository\ntprint.inf_amd64_neutral_4616c3de1949be6d\Amd64

One copy with size 828 KB
C:\Windows\System32\spool\drivers\x64

and one copy in the right directory, but size 0 KB!
C:\Windows\System32\spool\drivers\x64\3

-If you have either no result in .\3 or it is size zero, this method may work for you. Copy a non-zero sized version of the dll (if there are multiple sizes, use the one from DriverStore) to the .\3 directory under C:\Windows\System32\spool\drivers\x64.
- If you are unsure how to do this, open a window and navigate to:
C:\Windows\System32\spool\drivers\x64\3
- Then right click on the dll in the search results (again, preferably from DriverStore) and select "copy"
- Then paste the dll into C:\Windows\System32\spool\drivers\x64\3. Note that you need admin priviledges. A window should pop up asking for permission, click "ok" or yes.

TL;DR (too long, didn't read) copy a working version from the Driver store to C:\Windows\System32\spool\drivers\x64\3.