@Henrique Marques ,
Does this issue occur with all database file?
- Please create a new database file and save to other location to check this issue.
- It's recommended to go to File > Options > Trust Center > Trust Center Settings > Trusted Locations > Add new location, add the path of database as a trusted location.
- You may also go to Control Panel > Program Files, find and right click the Access, choose Change, perform a online repair for it.
Besides, have you split the database?
If so, I suggest you refer to the similar thread "Split MS Access database - can't open backend - potential security concern".
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Any questions, please let me know.
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