Last week Microsoft released the January 2019 Patch Tuesday updates and included in the release were two updates that caused problems connecting to ntework shares on Windows 7 and Windows Server 2008 R2. On January 11th, Microsoft has released a a stand-alone update that resolves this issue. KB4487345 fixes the issue where local users who are part of the local Administrators group may not be able to remotely access shares. This does not affect domain accounts in the local “Administrators”” group.”
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-releases-kb4487345-update-to-fix-windows-7-share-issues/